TERM - 2 10 2022 SCIENCE SAMPLE PAPERS (Strictly Based on the Sample Paper issued by CBSE) Full Marks Pvt Ltd (Progressive Educational Publishers) New Delhi-110002
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Note from the Publishers Science-X (Term-2) based on the latest Sample Question Paper issued by CBSE on 14th January 2022 for 2022 (Term-2) Board Examination. Each Practice Paper is developed by highly experienced subject experts as per the level and the pattern followed by the CBSE. These Practice Papers will familiarise the students with the questioning pattern. This book contains 11 Practice Papers (3 Solved, 7 Unsolved and 1 issued by CBSE with Marking Scheme). Undoubtedly, students will get some parameter to evaluate their preparation for better performance. Features of Sample Papers • Designed exclusively to test the knowledge and preparation level of students. • Latest CBSE Sample Question Paper have been given with Marking Scheme. • Each Practice Paper covers the weightage of each unit/chapter as per the latest syllabus issued by CBSE. Any suggestions for further improvement of this book will be thankfully received and incorporated in the next edition. (iii)
CONTENTS SOLVED SAMPLE PAPERS 1. Practice Paper – 1........................................................................................................................................................ 7 2. Practice Paper – 2...................................................................................................................................................... 12 3. Practice Paper – 3...................................................................................................................................................... 18 UNSOLVED SAMPLE PAPERS 4. Practice Paper – 4...................................................................................................................................................... 25 5. Practice Paper – 5...................................................................................................................................................... 27 6. Practice Paper – 6...................................................................................................................................................... 31 7. Practice Paper – 7...................................................................................................................................................... 34 8. Practice Paper – 8...................................................................................................................................................... 37 9. Practice Paper – 9...................................................................................................................................................... 40 10. Practice Paper – 10.................................................................................................................................................... 43 11. Practice Paper – 11 [CBSE Sample Paper 2021-22 (Term-2) with Marking Scheme] �������������������������������������������� 46 (iv)
SCIENCE SCIENCE Practice Papers 3 Solved Practice Papers 7 Unsolved Practice Papers CBSE Sample Question Paper 2021-22 (Term-2)
SCIENCE Marks WEIGHTAGE 10 CLASS-X (TERM-2) 13 12 Unit Term-II 05 I Chemical Substances-Nature and Behaviour: Chapter 4 and 5 40 II World of Living: Chapter 8 and 9 10 IV Effects of Current: Chapter 12 and 13 50 V Natural Resources: Chapter 15 Total Internal Assessment: Term II Total
1Practice Paper– Time Allowed: 2 Hours Maximum Marks: 40 General Instructions: 1. All questions are compulsory. 2. This question paper has three sections and 15 questions. All questions are compulsory. 3. Section – A has 7 questions of 2 marks each; Section – B has 6 questions of 3 marks each; Section – C has 2 case based questions of 4 marks each. 4. Internal choices have been provided in some questions. A student has to attempt only one of the alternatives in such questions. SECTION-A 1. Carbon is known to form compounds with many elements. Write the electron dot structure of compound formed with (i) Chlorine, (ii) Oxygen. 2 Ans. (i) CCl4 (ii) CO2 2 2. The table shows the electronic configuration of four elements A, B, C, D. Element A B C D 2, 8, 1 2, 8, 8 2, 8, 8, 1 2, 8, 4 Electronic Configuration (i) Which two elements belong to same group and will form unipositively charged cation? Give reason. (ii) Which element will form covalent bonds and why? Ans. (i) ‘A’ and ‘C’ belong group 1 and form unipositive cation because they have same valence electron equal to 1. After losing one electron they will become stable. (ii) ‘D’ will form covalent bond because it can share four electrons to become stable. 3. Give two differences between male gamete and female gamete. 2 Ans. Male gamete Female gamete I t is smaller in size. I t is bigger in size. I t is motile. I t is non-motile. 4. Name the type of asexual reproduction in: 2 (a) Planaria (b) Rhizopus (c) Spirogyra (d) Hydra A ns. (a) Regeneration (b) Spore formation (c) Fragmentation (d) Budding 5. A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything whether the light eye colour trait is dominant or recessive? Why or why not? 2 A ns. We cannot predict because information is not sufficient. We can decide dominant or recessive trait of we have the data for at least three generations. More information is required. Or (a) What is genetic constitution of human sperm? (b) Mention the chromosome pair present in zygote determining the sex of male child. 7
Ans. (a) 22 + Y chromosome or 22 + X chromosomes. (b) (22 + X + 22 + Y) = (44 + X + Y) chromosomes are present in male child. 6. How is strength of magnetic field near a straight current carrying conductor: 2 (i) related to the strength of current? (ii) affected when the direction of flow of current is reversed? Or (i) Why does a compass needle get defected when brought near a current carrying conductor? (ii) What happens to the deflection of needle when current in the conductor is increased? Ans. (i) The strength of magnetic field is directly proportional to the strength of current. (ii) If we reverse the direction of current, the direction of magnetic field will also be reversed. Or (i) It is because current carrying conductor produces a magnetic field which superimposes with magnetic field of compass needle due to which needle of compass gets deflected. (ii) The deflection in the magnetic needle will increase as the strength of current increases. 7. The following is form of food chain : I nsect, Hawk, Grass, Snake, Frog 2 Which of these will have highest concentration of non-biodegradable chemicals? Name the phenomenon. Or Construct an aquatic food chain showing four trophic levels. Hawk will have highest concentration of non-biodegradable chemicals. This process is called bio-magnification. Or Hawk or Sea gull (Top carnivore) Fish (carnivore) Crustacean (carnivore) Zooplankton (herbivore) Phytoplankton (producer) Aquatic food chain SECTION-B 8. Choose an element from period 2 of modern periodic table that matches the description given below. Give reason. 3 (a) Element forming large number of compounds. (b) It has same valency as magnesium. (c) It has variable valency and is member of nitrogen family (Group 15). A ns. (a) Carbon because of tetravalency and catenation. (b) Beryllium (2, 2) has same valency as Mg (2, 8, 2) (c) Phosphorus, + 3, + 5 e.g., It forms PCl3 and PCl5. 3 9. (a) How many isomers are possible for the compound with the molecular formula C4H10? Draw the electron dot structure of straight chain isomer. (b) How will you prove C4H6 and C5H8 belong to same homologous series. Or A carbon compound ‘A’ (C2H4O2) having melting point 291K and boiling point 118°C, is soluble is water and ionises in aqueous solution. It will turn blue litmus red. (a) Identify ‘A’ and draw its electron dot structure. (b) Give the structural formula of any two homologous of ‘A’. 8n Science– X
Ans. (a) It has two isomers: HHHH |||| H—C—C—C—C—H |||| HHHH (b) They belong to same homologous series. Alkyne with general formula CnH2 n – 2 n = 4 C4H6 n = 5 C5H8 Or O H :O.. ..: .. .. || (a) ‘A’ is CH3—C—OH H : C: C : O. . : H .. H (b) (i) (ii) 10. Study the following cross showing self pollination in F1, fill in the blank and answer the questions that follow: 3 Parents RRYY × rryy Round, yellow Wrinkled, green F1 Rr Yy × .......................... What are the combinations of character in the F2 progeny? What are their ratios? A ns. F1 progeny is Rr Yy—Round, Yellow Combinations of character in the F2 progeny are: (i) Round yellow — 9 (Both dominant traits) (ii) Round green — 3 (One recessive, one dominant) (iii) Wrinkled yellow — 3 (One dominant, one recessive) (iv) Wrinkled green — 1 (both recessive traits) The ratio is 9 : 3 : 3 : 1 11. (a) Compute the heat generated while transferring 96000 C of charge in one hour through a potential difference 3 of 50V. (b) What is cost of running AC of power 1000 W for 8 hours per day, electrical energy being charged ` 4.70 per kWh. Sol. (a) Q = 96000C, t = 1 hr = 60 × 60 = 3600s, V = 50V H = V × I × t = V × Q = 50 × 96000 = 50 × 96000 = 4800 kJ 1000 (b) Total power consumed = 1000 × 8 = 8000 watt hour = 8 kWh Cost per day = 8 × 4.70 = ` 37.60 Practice Paper–1 n 9
12. Find the current drawn from the battery by the network of four resistors as shown in the figure. 3 Or Study the following electric circuit and find the (i) current flowing through the circuit and (ii) the potential difference across 10 W resistor. A ns. R1, R2, R3 are in series combination and R4 is in parallel combination to these combination of resistors. Equivalent resistance of the given network is given as: 11 1 1 1 1 1 3+1 4 R = R4 + R1 + R2 + R3 = 10 + 10 + 10 + 10 = 10 + 30 = 30 = 30 \\ R = 30 = 7.5 Ω 4 V 3 30 2 ⇒ I = 0.4 A Current drawn from the battery I = R = 7.5 = 75 = 5 Or (i) Rs = R1 + R2 = 10 Ω + 20 Ω = 30 W V 3V I = IR× = 3=00.Ω1 = 0.1 A V (ii) V = R × 10 = 1 13. (i) What is the height of ozone from the equator? 3 (ii) Name the rays against which ozone layer provides protection. (iii) Name one effect of depletion of ozone layer. A ns. (i) 10 to 16 km (ii) UV rays (iii) Global warming. SECTION-C 14. In some animals, the temperature at which fertilised eggs are kept determines whether the animal developing in the egg will be male or female. In other animals, such as snails, individuals can change sex, that is sex is not genetically determined. In human beings, sex of individuals is largely genetically determined. All chromosomes in human beings are not paired. We have 22 pairs and one pair of sex chromosomes which is odd and not always a perfect pair. 4 10 n Science– X
(a) Which chromosomes are present in male and female respectively? (1) (b) Who is responsible for birth of a male child? Why? (1) (c) How many chromosomes are called autosomes? What does XXY chromosome denote? (2) Or (d) What is meant by XYX syndrome? Explain. A ns. (a) XY in male and XX in female. (b) Father is responsible for birth of male child because ‘Y’ chromosomes are only present in male. (c) 22 chromosomes are called autosomes. XXY is person with gender disorder, a person who is superficially male but carries an extra X or female chromosome. Or (d) XYX syndrome is rare chromosomal disorder that affects males. It is caused by an extra ‘X’ chromosome. Affected individuals are very tall. 15. A solenoid is a long helical coil of wire through which a current is run in order to create a magnetic field. The magnetic field of the solenoid is the superposition of the fields due to the current through each coil. It is nearly uniform inside the solenoid and close to zero outside and is similar to the field of a bar magnet having a north pole at one end and a south pole at the other depending upon the direction of current flow. The magnetic field produced in the solenoid is dependent on a few factors such as, the current in the coil, number of turns per unit length etc. The following graph is obtained by a researcher while doing an experiment to see the variation of the magnetic field with respect to the current in the solenoid. The unit of magnetic field as given in the graph attached is in milli-tesla (mT) and the current is given in ampere. 18 4 16 14 Magnetic field B (mT) 12 10 8 6 4 2 0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Current (A) (a) What will happen if a soft iron bar is placed inside the solenoid? (1) (b) What is relation between magnetic lines produced by bar magnet and solenoid? (1) (c) Observe the graph and give relationship between magnetic field produced with strength of electric current. How is magnetic force in magnetic field related to current. (2) Or Give observations based on graph. What is magnetic field at 0.8 A current. Ans. (a) The bar will be magnetised as long as there is current in the circuit. (b) The magnetic field lines produced by solenoid is similar to that of bar magnet. (c) The magnetic field is directly proportional tod strength of current passed through solenoid. Magnetic force on current in magnetic field = current × displacement across the magnetic field. Or (i) The magnetic field is directly proportional to current. (ii) At 0.8 A current, the magnetic field is 13 mT. Practice Paper–1 n 11
2Practice Paper– Maximum Marks: 40 Time Allowed: 2 Hours General Instructions: Same as Practice Paper-1. SECTION-A 1. Atoms of an element has five valence electrons in its valence shell. The element is major component of air. It exist as diatomic molecule: 2 (i) Identify the element. (ii) Show the bond formed between two atoms of this element. (iii) Write the nature of bond between the two atoms. Ans. (i) Nitrogen (ii) (iii) Triple covalent bond. 2. 2 (i) Which element will form most basic oxide? (ii) Which element will form acidic oxide? (iii) Which element is non-metal with valency 1? (iv) Which element is metal with valency 2? Ans. (i) ‘A’ will form most basic oxide. (ii) ‘C’ will form acidic oxide. (iii) ‘C’ is non-metal with valency 1. (iv) ‘B’ is metal with valency 2. 3. Name the most suitable method of raising a banana plant. Is this mode of reproduction sexual or asexual? List two advantages of growing plants by such method. 2 Ans. • Vegetative propagation • Asexual Advantages: (i) Plant can bear flowers and fruits earlier. (ii) All plants produced are genetically similar to parent plant. (iii) Plants that have lost the capacity to produce viable seeds can be grown by this method. (Any Two) 12
4. Name the process of reproduction of yeast. Design an activity to observe this mode of reproduction in school laboratory. 2 A ns. • Budding Activity: 1. Dissolved sugar in water. 2. Add yeast to it and keep it in a warm place. 3. After 2 hours, put a drop of yeast culture on a slide and observe under microscope. Buds will be observed showing that yeast reproduce by budding. 5. We can see eyes in planaria, insects, octopus and vertebrates: 2 (i) Can eyes be grouped together in case of above mentioned organisms to establish a common evolutionary origin? Why? (ii) Can these organisms be grouped together on the basis of eyes they possess? Give justification to your answer. Or State the evidence to prove that birds have evolved from reptiles. Ans. (i) Yes, eyes can be grouped together, which have evolved over generation from imperfect eyes in Planaria to perfect eyes in vertebrates. (ii) No, they cannot be grouped together on the basis of their eyes because they belong to different phylo. Or Some species like dinosaurs had feathers although they could not fly using feathers. Birds later on adapted the feathers for flight which proves that birds are closely related to reptiles. 6. Study the diagram given below and answer the questions that follow: 2 NS S S N N NS Iron filings near the bar magnet Drawing a magnetic field line with align themselves along the field lines. the help of a compass needle (i) Why do iron filings arrange in this pattern? (ii) Why do the iron filings form closed curves near the bar magnet? (iii) What does this pattern demonstrate? Or (a) What is role of split rings in an electric motor? (b) Explain one way to induce current in the coil. Ans. (i) Iron filings align themselves along the magnetic field lines. (ii) Because magnetic field lines are closed curves. (iii) These demonstrate shape of magnetic field. Or (a) It acts as a commutator in DC (direct current) motor. The direction of current through the coil is reversed with the half of split rings after every half rotation of coil, direction of current in the rotating coil is reversed and coil continues to rotate in the same direction producing direct current. (b) It can be done either by moving the coil in magnetic field or by changing magnetic field around the coil. Practice Paper–2 n 13
7. (a) What will happen if deer are missing in the following food chain? 2 Grass → Deer→ Tiger 3 (b) Out of ponds, forests, aquariums and crops fields which are natural ecosystems. 3 Or What are aims of water shed management? A ns. (a) Tigers will die. (b) Ponds and forests are natural ecosystems. Or The aim of water management is: (i) Soil and water conservation. (ii) Mitigation of droughts and floods. (iii) Increase the life of the down stream dams and reserviours. (Any two) SECTION-B 8. The position of certain elements in Modern periodic table are shown below: Group 1 2 3 to 12 13 14 15 16 17 18 → ↓ Period 1G H 2A I BC 3D E F Using the above table answer the following questions giving reasons: (i) Which element will form covalent compound? (ii) Which element is non-metal with valency 2? (iii) Which element is metal with valency 2? (iv) Out of H, C, F which has largest atomic size. (v) To which family H, C, F belong? Ans. (i) ‘E’ will form covalent compounds because it can share four electrons to complete its octet. (ii) ‘B’ because it has 6 valence electrons, it can gain 2 electrons to become stable. (iii) ‘D’ because it can lose 2 electrons to become stable. (iv) ‘F’ has largest atomic size due to highest number of shells. (v) Nobel gases. 9. (a) Name the cyclic unsaturated carbon compound. Write its structural formula. (b) Covalent compounds have low melting and boiling points, Why? (c) How are covalent bonds formed? Or Consider to molecular formula of the carbon compounds (a) and (b) given below: (a) C3H8O (b) C3H6O2 (i) Identify the functional groups in (a) and (b) and write their structures. (ii) Are (a) and (b) isomers? Give reason. 14 n Science– X
Ans. (a) Benzene, (b) It is due to weak forces of attraction between molecules. (c) Covalent bonds are formed by equal sharing of electrons. Or (i) (a) CH3CH2—CH2—OH Functional group —OH (alcohol) (b) CH3CH2—COOH Functional group —COOH (Carboxylic acid) Or CH3COOCH3 Functional group —Ester (ii) (a) and (b) are not isomers because they differ in molecular formula. 10. (a) Why is the F1 progeny always of tall plants when a tall pea plant is crossed with short pea plant? 3 (b) How is F2 progeny obtained by self pollination of F1 progeny different from F1 progeny? Give reason for this observation . (c) State a conclusion that can be drawn on the basis of this observation. Ans. (a) It is because tallness is the dominant trait. (b) The recessive character is expressed in F2 generation when two copies of the recessive trait are present together/ (tt). (c) In the F2 progeny, the dominant character is also expressed along with the recessive character in ratio of 3 : 1 respectively. 11. (a) State the relationship correlating the electric current flowing in a conductor and the voltage applied across it. 3 Also draw a graph to show this relationship. (b) Find the resistance of a conductor if the electric current through it is 0.35V when the potential difference across it is 1.4V. Ans. (a) V ∝ I or V = Constant or V = IR I (b) I = 0.35 A, V = 1.4 V R = V = 1.4 = 4 Ω I 0.35 12. In the circuit given below calculate : 3 (i) Current through each resistor. (ii) Total current in the circuit. (iii) Total effective resistance of the circuit. Practice Paper–2 n 15
Or Two identical resistors, each of resistance 15W, are connected in series to a battery of 6V, calculate the power consumed in the combination of resistors. A ns. (i) I1 = V = 6 = 0.6 A R1 10 I2 = V = 6 = 0.3 A R2 20 I3 = V = 6 = 0.2 A R3 30 (ii) I = I1 + I2 + I3 = 0.6 A + 0.3 A + 02 A = 1.1 A (iii) Reff. = V = 6V = 5.4 Ω I 1.1 A Or In series RS = R1 + R2 = 15 W + 15 W = 30 W I = V = 6 V = 0.2 A RS 30 Ω P = V × I = 6 V × 0.2 A = 1.2 W 13. When the government banned the use of polybags in Delhi, the vegetable grocers found it difficult as it affected their sales. The market committee held a meeting and decided to spread awareness about harmful effect of polybags. 3 (i) How will you convince people that plastics are harmful to the environment? (ii) What alternatives of polythene bags do we have, which are environment friendly? (iii) Not many people in Delhi have stopped using polythene bags even though they are officially banned. How can schools enaculate environmental values in students? Ans. (i) They need to be told that cows and other animals eat polythene which is fatal for them. Coloured polythene is also very harmful for vegetables and fruits. (ii) Paper bags, jute bags, Bags of biodegradable materials are ecofriendly and carrying your own shopping bag is also more convenient. (iii) Schools must teach students to protect environment. They should make paper bags and distribute to small shopkeepers regularly so that gradually their habits will change. SECTION-C 14. The growing size of human population is a cause of concern for all people. The rate of birth and death in a given population will determine its size. Reproduction is a process in which organisms increase their population. The person of sexual maturation for reproduction is gradual and takes place while general body growth is still going on. Some degree of sexual maturation does not necessarily mean that mind or body is ready for sexual acts or for having and bringing up babies. Various contraceptives devices are being used by human beings to control the size of population. 4 (a) What is result of reckless female foeticide? (1) (b) What contraceptive method changes the hormonal balance of the body? (1) (c) List two common signs of sexual maturation in boys and girls. (2) Or (d) Explain two factors that are responsible to determine size of population. 16 n Science– X
Ans. (a) Imbalance of boys and girls ratio. In most of Indian states boys are more than girls. (b) Oral pills changes the harmonal balance. (c) Thick hair growth in armpits/genital area. Thinner hair on arms, legs, face. Occurrence of pimples, more active oil secretion from glands in skin. Or (d) (i) Rate of birth and death. (ii) Early marriage of boys and girls. (iii) Non-use of contraceptive methods. (Any two) 15. A magnetic stripe card, also referred to as a swipe card or magstripe, is a plastic card with a magnetic strip attached on its surface. This stripe is made of tiny iron-based components whose magnetism can be modified and can therefore be used to store information. A magstripe is quite similar to a magnetic recording tape, which you might find in videotape or a music cassette. The magnetic strip on a card can be ‘written’ or encoded with information because the tiny iron-based particles that make up the strip can be magnetised in different directions by a device that produces a strong magnetic field. This device is a ‘solenoid’, which is basically a coil wound into a tightly packed helix. The wire is wound around a high-permeable, metallic core that produces a strong magnetic field when a current is passed through it. This device encodes the required information onto the stripe, which is then pasted on a plastic card. When a card with a magnetic strip is moved back and forth over the ‘reader head’ , a voltage is induced in the coils of the card reader device. A card reader consists of solenoid too – the same component that is used to write information in the magnetic strip. This voltage can be amplified and recorded electronically, which is finally read by a computer (or a processor installed within the reader) to authenticate a user (in the case of identity cards) or a transaction (in the case of credit/debit cards). 4 (a) Name any two devices that use magnetic theory to record data. (1) (b) On which part the information of users are stored in ATM card? (1) (c) Give two factors which result in increase of force on wire inside magnetic field. (2) Or (d) Give two factors on which magnetic field strength depend. Ans. (a) Hotel key cards, Audiotapes, CD’s, ATM (Any two) (b) It is stored on magnetic strip of the card. (c) (i) Strength of current is increased. (ii) Strength of magnetic field is increased. (iii) Length of wire inside magnetic field is increased. Or (d) (i) Magnitude of current (ii) Number of turns. Practice Paper–2 n 17
3Practice Paper– Maximum Marks: 40 Time Allowed: 2 Hours General Instructions: Same as Practice Paper-1. SECTION-A 1. (a) On the basis of electronic configuration of 9 X, write the group number and period number of element ‘X’. 2 5 (b) An element ‘X’ with atomic number 11 forms a compound with element ‘Y’ with atomic number 8. What is formula of the compound formed? Ans. (a) X(5) has electronic configuration 2, 3. Hence the group number is 13 and the period is 2. (b) X(11) 2, 8, 1 Y(8) 2, 6 X Y 1 2 X2Y is formula of compound formed. 2 2. Write the structural formula of (i) Butanone and (ii) Pentanonic acid. Ans. (i) (ii) 3. How do sperms reach the female genital tract? Where does fertilization and implantation of the embryo take place? 2 A ns. Sperms travel upwards through uterus to oviduct where they meet an ovum and hence fertilize it. Fertilization takes place in oviduct to give rise to single-celled zygote. The zygote divides to become multicellular embryo which gets fixed in uterus. 4. What is a clone? Why do offsprings formed by asexual reproduction exhibit remarkable similarity? 2 A ns. Clones are organisms which are exact genetics copies of their parents. Their DNA is exactly identical to their parents, which is the cause of remarkable similarity. 5. A cross was carried out between pure breed tall pea plant with pure dwarf pea plant and F1 progeny was obtained. Later, F1 progeny was selfed to obtain F2 progeny. Answer the following questions: 2 (a) What is the phenotype of the F1 progeny and why? (b) Give the phenotypic ratio of the F2 progeny. (c) Why is F2 progeny different from the F1 progeny? Or List two differences in tabular form between dominant traits and recessive traits. Ans. (a) Tall because it is a dominant trait whereas dwarf is a recessive trait. (b) 3 : 1 is ratio between tall to dwarf. (c) In F2 generation, recessive genes are also expressed in homozygous condition. 18
Or Dominant traits Recessive traits It expresses itself with or without the It is able to express itself only in the presence of recessive trait. absence of dominant trait. F or example: tall plant, round seed, violet Dwarf plant, wrinkled seed, white flower, flower etc. are dominant traits in a pea etc. are recessive traits in a pea plant. plant. 6. Magnetic field lines of two magnets are shown in figure A and figure B. 2 (A) (B) Select the figure that represents the correct pattern of field lines. Give reasons for your answer. Also name the poles of the magnets facing each other. Or The magnetic field associated with a current carrying straight conductor is in anticlockwise direction. If the conductor was held along the east-west direction, what will be the direction of current through it? Name and state the rule applied to determine the direction of current. Ans. Figure ‘B’ represents correct pattern of magnetic field lines because magnetic field lines never intersect each other. If these intersect, there will be two directions of the magnetic field at the point of intersection, which is not possible. In figure B. field lines are emerging (going away) from the magnet, so both the poles are north poles. Or When the observer observes the direction of magnetic field from west then the direction of current is from east to west and if observer is at east side then the direction of current is from west to east. Right hand thumb rule: If we hold a current carrying conductor in our right hand in such a way that stretched thumb is along the direction of the current, then curls of fingers around the conductor represents the direction of magnetic field lines. 7. (a) Out of River, crop field, forest and ocean, which one is an artificial ecosystem? 2 (b) 50,000 kJ of energy that passes from the second trophic level to the third trophic level in food chain, how much energy passes and where does it go? Or Arrange the following in the food chain (a) frogs, insects, birds, grass (b) fish, algae, small animal, big animal Ans. (a) Crop field is artificial ecosystem. (b) 50000 × 10 = 5000 kJ of energy is transferred. 100 It is stored in body tissues of third trophic level. Or (a) Grass → Insect → Frogs → Birds (b) Algae → Small animals → Fish → Big animals SECTION-B 8. (a) How many isomers are possible for the compound with molecular formula C3H6O? Write their structural formula and electron dot diagram. 3 Practice Paper–3 n 19
(b) Which of the following compounds belong to same homologous series? C3H4, C2H6, C2H6O, CH4O, C2H4O2 A ns. (a) There are two isomers (b) CH4O (CH3OH) and (C2H6O (C2H5OH) belong to same homologous series. 3 9. From the elements Li, K, C, Al, Mg, S, identify the : (a) elements belonging to same group (b) element which has tendency to lose two electrons (c) element which prefers sharing of electrons to complete the octet. (d) most metallic element (e) element which forms acidic oxide (f) element that belongs to Group 13. Or (a) An element ‘X’ with atomic number 12 forms a compound with element ‘Y’ with atomic number 17. What is formula and nature of compound formed? (b) Out of Na, S, Cl, Mg, which element (i) will form Basic oxide (ii) belongs to group 16 (iii) will gain 2 electrons (iv) can lose one electron? Ans. (a) Li, K (b) Mg (c) C (d) K (e) S (f) Al (a) X Y X (12) 2, 8, 2 Or Valency = 2 1 2 Y (17) 2, 8, 7 Valency = 1 XY2 (Ionic compound) (b) (i) Na and Mg will form basic oxides became these are metals. (ii) S (2, 8, 6) belongs to group 16 (iii) S will gain 2 electrons to become stable. (iv) Na can lose one electron to become stable. 10. Explain the Mendel’s concept of heredity, by giving three points. 3 Ans. (i) Mendel worked on pea plant. (ii) He found that traits are controlled by genes which come in pairs. (iii) Genes are inherited as separate units, one from each parent. 20 n Science– X
11. An electric heater of resistance 8 W draws 15 A current from the supply mains for 2 hours. Calculate the rate at which heat is developed in the heater. 3 A ns. R = 8 W, I = 15A, t = 2 hours Rate of heat developed = Η = I2 × R × t t t = I2 × R = (15)2 × 8 = 225 × 8 = 1800 W = 1.8 kW 12. In the given circuit, A, B, C and D are four lamps connected with a battery of 60V. 3 60 V 3A 4A 5A 3A ABCD Analyse the circuit to answer the following questions. (i) What kind of combination are the lamps arranged in (series or parallel)? (ii) Explain with reference to your above answer, what are the advantages (any two) of this combination of lamps? (iii) Calculate the resistance of circuit. Or Explain the following: (i) Why is tungsten used almost exclusively for filament of electric lamps? (ii) Why are the conductors of electric heating devices, such as bread-toaster and electric iron, made of an alloy rather than a pure metal? (iii) Why is series arrangement not used for domestic circuits? Ans. (i) The lamps are in parallel. (ii) Advantages: I f one lamp is faulty, it will not affect the working of the other lamps. They will also be using the full potential of the battery as they are connected in parallel. (iii) The total current in the circuit = (3 + 4 + 5 + 3) A = 15A The Voltage = 60 V V = IR and hence R = V/I R = 60/15 W = 4 W Or (i) It has high resistance and high melting point. So it does not melt when current is passed through it. (ii) Alloys have more resistivity and higher melting point than pure metals. (iii) It increases the resistance and current decreases. Also if one component fails to work, others will also not work. 13. (a) Water is an elixir of life, a very important natural resource. Your Science teacher wants you to prepare a plan 3 for a formative assessment activity, “How to save water, the vital natural resource”. Write any two ways that you will suggest to bring awareness in your neighbourhood, on ‘how to save water’. (b) Name and explain any one way by which underground water table does not go down further. A ns. (a) Water is one of the most precious natural resources that has vital importance in our lives. It is an essential component of the human body and is used almost everywhere in our day-to-day activities, such as cooking, Practice Paper–3 n 21
washing, in agriculture and industries. It is an indispensable part of our life, without which the life on earth is not possible. However, the amount of fresh water available for sustaining life is very less. So, it is very important to conserve water. For creating awareness among people, we can adopt the following two ways. (i) Door to door campaigning. (ii) Nukkad Nataks (b) Underground water table can be recharged through rainwater harvesting. Rainwater harvesting is a process by which rain water is collected and stored for the purpose of recharging the ground water or for future use like for irrigation and agriculture, for livestock, etc. In India, rainwater harvesting is an old tradition, which is followed till now in many parts of India. For example, bawris are traditional architectural rainwater harvesters that were built for collecting water, in the state of Rajasthan. There are two ways of rainwater harvesting: (i) Surface runoff harvesting: In urban areas, rain water that flows away from the surface can be collected and used for various purposes. (ii) Rooftop rainwater harvesting: The rainwater on the roofs of the buildings is collected through canals that drains the water into ground water reservoirs. This stored water can later be utilised. SECTION-C 14. The male reproductive system consist of portions which produce the germ-cells and other portions that deliver the germ-cells to the site of fertilisation. Testes are located outside the abdominal cavity in scrotum because sperm formation requires a lower temperature than normal body temperature. It also has a role of secretion of male sex hormone which brings changes in appearance seen in boys at the time of puberty. Vas deferens unites with tube coming from urinary bladder. Urethra is a common passage for sperms and urine. Prostate gland and seminal vesicles add their secretions so that sperms are now in fluid. 4 Seminal vesicle Ureter Bladder Vas deferens Prostate gland Penis Urethra Testis Scrotum Human-male reproductive system (a) Name the sex hormone associated with males. What is nature of semen? (1) (b) Why are testes located outside the abdominal cavity? (1) (c) What is role of fluid in semen? (Give two points). (2) Or (d) Give two characteristics of sperms. Ans. (a) Testosterone, Semen is slightly basic in nature. (b) It is because sperm formation needs lower temperature than body temperature. (c) (i) Fluid provides nutrition to sperms. 22 n Science– X
(ii) Fluid helps to bind the sperm together. (iii) Fluid help in transportation of sperms. (Any two) Or (i) Sperm and urine have same passage from urethra. (ii) Sperms have long tail that helps them to move forward. (iii) Sperms contain genetic material. 15. An electric motor converts electrical energy into mechanical energy. It works on the principle that a current carrying conductor placed in a magnetic field experiences a force. 4 Following are the essential parts of an electric motor. (i) Coil: It is a rectangular coil of insulated copper wire having large number of turns. (ii) A large permanent magnet provides strong magnetic field between its pole pieces. The coil rotates between these pole pieces. (iii) Split rings: The two ends of coil are connected to two split rings, which are two halves of slip rings. NS motion motion electron electron brush brush split ring commutator DC power supply Working : W hen a current is passed through the coil, the direction of current in AB and CD is in opposite direction but both are perpendicular to magnetic field. Therefore, by Fleming’s left hand rule, arm AB of the coil experiences an upward force and arm CD experiences a downward force. These two forces being equal and opposite to each other form a couple which rotates the coil. Arms BC and DA are parallel to the field and the force between them is zero. The forces on AB and CD turns the coil in clockwise direction. After half revolution, the split rings change their position. So the direction of current in the coil reverses. The couple now acting on the coil again moves it in clockwise direction. Due to the function of split ring commutator and brushes, coil continues to turn in clockwise direction. Split ring commutator changes direction after every half rotation, so that the direction of current going in the coil also reverses. As a result, the coil continues to rotate in one direction. So, the electrical energy given to the coil changes into mechanical energy. (a) Out of ceiling fan, blender, geyser, washing machine, which one is not based on magnetic effect of current and does not use electric motor? (1) (b) Which of the domestic appliances consumes maximum power out of iron, fan, tube, blender, airconditioner? (1) (c) Ramesh replaced all his 100 watt bulbs, total 8 with LED of 8 watts. If he uses bulbs for 8 hours per day, how much cost he will save per month if ` 5.70 per kWh is charged? (2) Practice Paper–3 n 23
Or (d) Neelam has one air conditioner of 2 kW which runs for 8 hours per day, fan (50 watt) for 12 hours every day. What will be her total cost per month if electricity charges are ` 5.00 per kWh? A ns. (a) Geyser is based on heating effect of current and not on magnetic effect of current. (b) Air conditioner. (c) 8 bulbs of 100 W consumes = 800 W 8 LED of 8 W consume = 64 W Power saved = 736 W Cost saved = 736 × 30 × 5.70 = 22080 × 5.70 1000 1000 = 22.08 kWh × 5.70 Cost = ` 125.85 Or (d) Air conditioner consumers = 30 × 2 × 8 = 480 kWh per month Fan consumes = 50W × 12 × 30 = 18 kWh 1000 Total cost = 498 × 5 = ` 2490 24 n Science– X
4Practice Paper– Time Allowed: 2 Hours Maximum Marks: 40 General Instructions: Same as Practice Paper-1. SECTION-A 1. Draw the electron dot diagrams of 2 2 (i) H2O (ii) C2H4 2. In second period, Li, Be, B, C, N, O, F (a) Which element has smallest atomic size and why? (b) Which elements are metals and why? 3. What is importance of DNA copying in reproduction? 2 4. Can you think the reasons why more complex organisms can not give rise to new individuals through regeneration? 2 5. Why are small number of surviving tigers a cause of worry from genetics points of view? 2 Or (a) State Mendel’s second law of inheritances. (b) What is monohybrid cross? 6. Under what conditions a permanent electromagnet is obtained if a current carrying solenoid is used? Support your 2 answer with the help of a labeled circuit diagram. Or What is meant by electromagnetic induction? State the rule which helps to determine the direction of induced current. 7. Study the following food chain: 2 Grass → Sheep or Goat → Man; Algae → Fish → Man Who is the ultimate sufferer of using pesticides like DDT on land and in water? Give reason. Or Energy flow is unidirectional in food chain. Explain. SECTION-B 8. (a) State the common characteristic of the following elements: 3 Boron, Silicon, Germanium and Arsenic 3 (b) State the periodic law on which the ‘Modern Periodic Table’ is based. (c) Out of Li, Na, P, Al, which element will form acidic oxide and why? 9. (a) Covalent compounds are generally poor conductors of electricity, why? (b) Why does carbon show property of catenation of maximum extent? (c) What is general formula of hormologous series of alkynes? Or (a) Carbon forms covalent bonds, why? (b) Write isomers of C4H10. Write electron dot diagram of branched isomer. 25
10. What are homologous structures? Give an example. Is it necessary that homologous structures always have 3 common ancestor? Justify your statement. Or Define the term self pollination. Differentiate between self pollination and cross pollination. What is significance of pollination? 11. Find the ratio of resistances of two copper rods ‘X’ and ‘Y’ of lengths 30 cm and 10 cm respectively and having 3 radii 2 cm and 1 cm respectively. 12. (a) For the combination of resistors shown in the following figure, find the equivalent resistance between M and N. 3 (b) State Jonle’s law of heating. 13. What is meant by food chain? ‘The number of trophic levels in food chain is limited.’ Give reason to justify the statement. 3 SECTION-C 14. A green stemmed rose plant denoted by GG and a brown stemmed rose plant denoted by gg are allowed to undergo a cross with each other. 4 (a) What will be colour of stem in F1 progeny? (1) (b) What will be ratio of GG and gg in F2 progeny? (1) (c) What will be percentage of brown stemmed plants in F2 progeny if F1 plants are (i) self pollinated, (ii) cross pollinated? (2) Or (d) Based on the findings of this cross, draw two conclusions. 15. Mrs Mala was demonstrating an experiment in her class with the set up shown in diagram. She took a long straight copper wire, three cells of 1.5V each, and a plug key and connected all of them in series as shown in Fig. She placed the straight wire parallel to and over a compass and plug the key in the circuit. 4 (a) What is the principle which Mrs Mala is applying to demonstrate? (1) (b) What is direction of deflection of the north pole of needle? (1) (c) What happens when battery terminals are reverted? What will happen when magnitude of current is changed? (2) Or Draw two conclusions on the basis of the experiment and observations of the experiment. 26 n Science– X
5Practice Paper– Time Allowed: 2 Hours Maximum Marks: 40 General Instructions: Same as Practice Paper-1. SECTION-A 1. Define the term functional group. Identify the functional group present in: 2 HO || || (a) (b) H—C—C—OH | H 2. From the elements 39 A, 1248B, 186C and 40 D, identify 2 19 18 (a) the most electropositive element. (b) a noble gas (c) a metalloid (d) an element which can gain 2 electrons to attain nearest noble gas configuration. Or (a) How do atomic radii vary down the group? Give reason. (b) What happens to tendency to gain electrons from left to right along a period? 3. Draw a diagram showing germination of pollen on stigma of a flower and mark on it the following organs/parts: 2 (i) Pollen grain (ii) Pollen tube (ii) Stigma (iv) Female germ cell 2 4. (i) What does stamen contain? (ii) Why are seeds called products of sexual reproduction? (iii) What type of reproduction takes place in: (a) Amoeba, (b) Plasmodium? 5. After self pollination in pea plants with round, yellow seeds, following types of seeds were obtained by 2 Mendel. Seeds Round, yellow Round, green Wrinkled, yellow Wrinkled, green Number 630 216 202 64 Analyse the result and describe the mechanism of inheritance which explain these results. Or In humans, there is 50% probability of the birth of a boy and 50% probability that a girl will be born. Justify the statement on the basis of the mechanism of sex determination in human beings. 6. (a) A freely suspended magnet always rests in geographically which direction. Why? 2 (b) What is strength of magnetic field of a current carrying solenoid is at ends and at centre? (c) Out of neutron, proton, electron and a–particle, which one will experience a maximum force whole moving perpendicular to a uniform magnetic field and why? 27
Or (a) In a pattern of magnetic field lines due to bar magnet, how can the regions of relative strength be identified? Draw a neat and labelled diagram. (b) Compare the strength of magnetic field near the poles and the middle of a bar magnet. 2 7. Complete the following flow chart based on ecosystem and its components. Or Accumulation of harmful chemicals in our body can be avoided. Explain how this can be achieved. SECTION-B 8. What is meant by homologous series? Give two characteristics of homologous series explaining with the help of example. 3 9. Consider the following and answer the questions that follow: 3 Group 1 Group 2 Group 3 A BC D EF G HI (a) Amongst A, D, G which is most electropositive and why? (b) Atomic size of ‘H’ is bigger or smaller than B, why? (c) Write the formula of compound formed by the element ‘E’ with fluorine. Or Two elements ‘P’ and ‘Q’ belong to same period of the modern periodic table and are in Group 1 and 2 respectively. Compare the following characteristics in tabular form: (a) The number of valence electrons in their atoms (b) Their metallic character (c) The size of their atoms (d) The formula of their oxide (e) Their tendency to lose electrons 28 n Science– X
(f) The formula of their chlorides 10. (a) A tall plant is crossed with dwarf plant. What will be the ratio of homozygous tall and heterozygous dwarf plant 3 in F2 generation? (b) No two individuals are absolutely alike in a population, why? (c) All the variations in the species do not have equal chances of survival, explain. 3 11. An electric kettle of 2 kW works for 2 hours daily. Calculate the (a) energy consumed in SI unit and commercial unit. (b) Cost of running it in the month of June at a rate of ` 3.00 per unit. 12. Two resistors 3W and unknown resistance are connected in a series across a 12V battery. If the voltage drops to 3 6V, find : (a) potential across 3W resistance. (b) the current through unknown resistor ‘R’. (c) equivalent resistance of the circuit. Or A circuit is shown in diagram given below: (a) Find the value of R. 3 (b) Find the reading of ammeter. (c) Find the potential difference across the terminals of the battery. 13. (a) What are uses of coal and petroleum? (b) How does burning of fossil fuel affect our environment. (c) Suggest two measures for controlling carbon dioxide levels in atmosphere. SECTION-C 14. An electric motor is a rotating device that converts electrical energy into mechanical energy. Electric motor is used as an important component in electric fans, refrigerators, mixers, washing machines, computers, MP3 players etc. 4 (a) What is principle of electric motor? (1) (b) What is the function of split ring in electric motor? (1) (c) State the rule for the direction of force on current carrying conductor in magnetic field. In electric motor, what Practice Paper–5 n 29
is direction of force acting on arm AB and arm CD? (2) NS Or The coil and the axle ‘O’ mounted free to rotate about an axis in which direction? At half rotation what happens to direction of current? 15. Consider a group of 12 red beetles. They live in some bushes with green leaves. Their population will grow by sexual reproduction, and therefore, can generate variations. Let us imagine also that crow eat beetles. The more 4 beetles crow eat, the fewer beetles are available to reproduce. (a) If colour variation arise during reproduction,there is one beetle green in colour and can pass the colour on to its progeny, what are chance of survival of green beetle and what will happen to population? Give reason.(1) (b) If colour variation arises again, there is one blue coloured beetle which can also pass on the colour to its progeny, (1) what will happen initially? (c) If an elephant comes in and kills most of the beetles, few blue beetles survive, what will happen to population (2) of blue and red beetles. Give reason. Or Draw two conclusions about evolution on the basis of both the above situations. 30 n Science– X
6Practice Paper– Time Allowed: 2 Hours Maximum Marks: 40 General Instructions: Same as Practice Paper-1. SECTION-A 1. The portion of Modern periodic table is shown below: 2 I II 13 14 15 16 17 18 F BD A CE (i) Which element is most metallic? (ii) Which element is most non-metallic? (iii) Which element has 6 valence electrons? (iv) Which element has largest atomic size? 2 2. (a) Write molecular formula of alkane having 14 carbon atoms. (b) Write isomers of C4H8. 2 3. What is role for seminal vesicles and the prostate gland? 4. What are those organisms called which bear both the sex organs in the same individual? Give one example of 2 such organisms. 5. Why is variation beneficial for the species but not necessarily for the individual? Explain. 2 Or How can we say that change in genes can be brought by the change in DNA? 6. Two coils of insulated copper wire are wound over a non-conducting cylinder as shown. Coil 1 has comparatively 2 large number of turns. State your observations when: Coil 1 Coil 2 +– a (i) key ‘K’ is closed. (ii) key K is opened. Give reason for each of your observations. Or Give reason for the following. (i) There is either convergence or a divergence of magnetic field lines near the ends of current carrying straight solenoid. (ii) The current carrying solenoid when suspended freely rests along a particular direction. 7. What is biological magnification? Will the levels of this magnification be different at different levels of ecosystem? 2 Or Why is damage to ozone layer cause of concern? Give two steps which must be taken to limit this damage. 31
SECTION-B 8. (a) Draw electron dot diagram of H2O. 3 (b) Write first two members of alcohol homologous series. (c) What are saturated hydrocarbons? Give one example. 3 9. (a) What is formula of compound of phosphorus and hydrogen? (b) Why is potassium more reactive than lithium? (c) How many electrons Al(13) can lose to become stable? Or (a) Which element of Group17 can gain electron most easily? Why? (b) What type of compounds are formed between Group1 and Group 17 elements? Why? (c) Why do ionic compounds conduct electricity in aqueous solution but not in solid state? 10. (a) A man with blood group A marries a women with blood group O and their daughter has blood group O. Is 3 this information enough to tell you which of the traits—blood group A or O is dominant? Why or why not? (b) How do Mendel experiments show that traits are inherited independently. 11. Describe an activity along with labelled diagram to study the characteristics of magnetic field produced by a current carrying circular coil at its centre. 12. Calculate the effective resistance between A an B in the circuit given below: OR 3 (a) Find the minimum resistance that can be made using four resistors, each of 20 ohms. (b) List one disadvantage of using a series circuit at home? 13. (a) List two causes of damage to forests. (b) What are non-renewable sources of energy? Give one example. (c) Management of forest and wild life is a very challenging task? Explain. SECTION-C 14. Mr. Sharma, physic teacher completed the circuit as shown in diagram by connecting one cell in a gap XY and nichrome wire was used . He asked children to note down current reading in ammeter and potential difference from voltmeter across the nichrome wire. He repeated the experiment by using two cells in series and then three cell in series. 4 32 n Science– X
(a) What happens to voltmeter and ammeter reading when number of cells are increased? (1) (b) What will be resistance of nichrome wire? (1) (c) Draw a graph between V and I. How will you calculate ‘R’ from the graph? (2) Or If V = 6V and I = 1.5 A , What will be resistance? If V and I are changed, ‘R’ will change or remain same? 15. Mrs. Pandit, biology teacher took a moist slice of bread and kept on cool, moist and dark place on a petridish for one day. Next day, she shown the slice to the children with the help of magnifying glass. 4 (a) What was aim of experiment shown by Mrs. Pandit? (1) (b) What was observation on the surface of bread? Give reason. (1) (c) If bread is kept for few days, what will be change in observation and why? (2) Or What are conclusions drawn from the observations of the experiments? Practice Paper–6 n 33
7Practice Paper– Time Allowed: 2 Hours Maximum Marks: 40 General Instructions: Same as Practice Paper-1. SECTION-A 1. (a) Why is position of isotopes no disputed in modern periodic table? 2 (b) What is cause of periodicity of proportion in periodic table? 2 2. (a) Write electronic configuration of carbon. (b) How does carbon become stable in compounds? 2 3. What are STD (sexually transmitted diseases)? Give two examples. 2 4. What happens when (a) Bryophyllum leaf falls on the wet soil? (b) On maturation sporangia of Rhizopus burst? 5. Mendel took tall pea plants and short pea plants and produced F1 progeny through cross-fertilisation. What did Mendel observe in F1 progeny? Explain. 2 Or Give two differences between somatic variations and genetic variations. 6. (a) Two magnets are lying side by side as shown below. Draw magnetic field lines between poles P and Q. 2 S NS N PQ (b) Why does the degree of closeness of magnetic field lines near the pole signify. Or Draw the pattern of magnetic field lines through a bar magnet and around a current carrying solenoid separately. 7. (i) Construct a terrestrial food chain comprising of four trophic levels. 2 (ii) Why do we not find food chains of more than four trophic levels? Or (i) Calculate the amount of energy available to each trophic level if first trophic level has energy 20000 kJ in four trophic ecosystem. (b) What is meant by food web? SECTION-B 8. (a) What are unsaturated hydrocarbons? Give one example. 3 (b) Write isomers of C4H6. Write their electron dot structures. 3 9. Look at the given elements: 4200 Ca, 1480Ar, 20 Ne, 199F 10 (a) Identify two elements which belong to same group and why? (b) To which group and period they belong? (c) What will be formula of compound formed between 40 Ca and 19 F What will be nature of bond formed? 20 9 Or 34
(a) Identify two metals in elements belonging to third period of Modern periodic table. (b) What happens to atomic size from Na to Ar? Give reason. (c) What happens to tendency to lose electron from Na to Cl Why? 3 10. (a) If a trait 'A' exists in 10% population of an sexually reproducing species and a trait 'B' exists in 60% of the same population, which trait is likely to have arisen earlier? Justify you answer. (b) How do the creation of variation in species promote survival? 3 11. (a) An electric refrigerator rated 400 W operates 8 hours per day. What is cost of energy to operate it for 30 days at ` 3.00 per kWh? (b) Convert 1 kWh into joules. 12. If R1 = 10 W, R2 = 40 W, R3 = 30 W, R4 = 20 W and R5 = 60 W and a 12 V battery is connected to the arrangement. as 3 shown in circuit. R 1 R 1 I + – R + 3 K A • R – 4 R 5 (a) The total resistance in the circuit. (b) The total current flowing in the circuit. OR In the circuit shown in figure, below if R1, R2, R3 are 5W, 10W, 30W respectively, which have been connected to 12 V battery, calculate L• R1 M X P• R2 Q• Y R3 ST +V– • – A+ (a) the current through each resistor. (b) total current in the circuit. (c) total circuit resistance. 13. State any four personal choices you would like to make to reduce energy consumption and reducing pollution 3 without affecting the quality of life or work explaining how each one of them would keep you to do so. Practice Paper–7 n 35
SECTION-C 14. Mr. Ravinder, Physics teacher, took a coil of wire AB having a large number of turns and connected the ends of the coil to the galvanometer as shown in fig. He took a strong bar magnet and moved its north pole towards the end B of the coil. 4 (a) What change will you observe in the needle of galvanometer? What does it show? (1) (b) If Mr. Ravinder withdraws the north pole of the magnet away from the coil, what will happen to defection in galvanometer and what does it show? (1) (c) When the coil is kept stationary with respect to magnet, what happens to deflection in galvanometer and what do you conclude from this activity? (2) Or What is galvanometer? How does position of its needle show direction of current? 15. Mendel used a number of contrasting visible characters of garden peas—round/wrinked seeds, tall/short plants,white/violet flowers and so on. He took pea plant with different characteristics, a tall plant and a short plant, produced progeny from them and calculated the percentage of tall or short progeny. 4 (a) There were no half way characteristic in this first generation of F1 progeny, no medium height plants, why? (1) (b) Were all tall plants in F1 generation exactly same as the tall plants in parent generation? (1) (c) wWahseonbBseortvhaptiaornenatbaolupt lparnotgseannydofthpearreenFt1atlaplllapnltasnitns were reproduced by self pollination, what F1 and F2 generation respectively? (2) Or What are two conclusions of these experiments based on observations. 36 n Science– X
8Practice Paper– Time Allowed: 2 Hours Maximum Marks: 40 General Instructions: Same as Practice Paper-1. SECTION-A 1. (a) Out of C2H2, C3H6, C3H8, C2H6 and C3H4 which of them can be classified as alkynes? Give reason. 2 (b) Which functional group are present in: (i) CH3COCH3 (ii) CH3CH2CH2OH 2. (a) Li, Na, K belong to Doberriner’s triads. If atomic mass of Li is 7, Na is 23, what will be atomic mass of K?2 (b) Li Na K Cu Rb This arrangement shown in figure belongs to which law of classification? 2 3. (a) In which part of body, female germ cells or eggs are made? (b) When girl is born, how many immature eggs are present in her body? What happens when she reaches maturity? 4. How do hydra and planaria reproduce? Explain. 2 5. Give two factors that could lead to rise of new species. 2 Or Will geographical isolation be a major factor in the separation of a self pollinating plant species? Why or why not? 6. Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. 2 Apply the right hand rule to find out the direction of magnetic field inside and outside the loop. Or (a) The magnetic field in a given region is uniform. Draw a diagram to represent it. (b) How does magnetic field vary inside a straight solenoid carrying current at various points? 2 7. What is role of decomposers in ecosystem? Explain. Or Give any two ways in which non-biodegradable substances should affect the environment. SECTION-B 3 3 8. (a) How many single bonds are present in C4H10. (b) Draw structural formula of cyclohexane. (c) Why is graphite conductor of electricity whereas diamond is not? 9. (a) How do valence electron vary down the group and along the period? (b) What happens to atomic size when we move left to right in a period? Give reason. 37
(c) What happens to basic characters of oxides down the group? Give reason. Or Element with atomic numbers are given in parentheses P (3), Q (12), R (13) and S (20) (a) Which two elements have similar chemical properties and why? (b) Which element belongs to group 13 and third period and why? (c) Give the formula of : (i) oxide (ii) chloride of ‘P’. 10. (a) Give an example of characteristics being used to determine how close two species are in evolutionary terms. 3 (b) Why are traits acquired during the life time of an individual not inherited? 11. An electric iron consumers energy at a rate of 840 W when heating is at the maximum rate and 360 W when the 3 heating is at the minimum. The voltage is 220V. What are the current and the resistance in each case? 12. (a) A current of 0.5 A is drawn by filament in an electric bulb for 10 minutes. Find the amount of charge that flows 3 through the circuit. (b) Calculate the number of electrons constituting one coulomb of charge. Or (a) How much work is done in moving a charge of 2 C across two points having potential difference 12 V? (b) Name a device that helps to maintain potential difference across the conductor. 3 13. (a) List one benefit of rain water harvesting. (b) Name one water harvesting system practised in ancient India. (c) Give two benefits of building a dam. SECTION-C 14. Mendel's experiments with two contributing characters. 4 X RR, yy rr, YY (round, green) (Wrinkled, yellow) Gamets Ry ry F F 1 1 Rr, Yy (round, yellow) X FF 12 38 n Science– X
(a) How many round and yellow seeds and how many round green seed will be produced in F2?((11)) (b) What is their ratio in fFr2o?m (2) (c) What do we conclude this experiment? Or Explain Mandel’s concept of heredity by giving two points. 15. Physics teacher inserted a copper wire through the centre, normal to the plane of rectangular card board and connected the copper wire vertically as shown in diagram in series with the battery, a plug and a key. He sprinkled some iron filings uniformly on the card board and kept the rheostat in fixed position and noted the current through ammeter, closed the key so that current flows through the wire. He tapped the card board gently and asked the students to observe the pattern of the iron filings. 4 (a) What do concentric circles around the copper wire represent? (1) (b) What do arrows in the circles show? (1) (c) How can the direction of the magnetic field be found? Explain. (2) Or Does the direction of magnetic field lines get reversed if the direction of current is reversed? What will happen if current passed in the copper wire is increased? Practice Paper–8 n 39
9Practice Paper– Time Allowed: 2 Hours Maximum Marks: 40 General Instructions: Same as Practice Paper-1. SECTION-A 1. H ow do Mendel's experiments show that traits are inherited independently? 2 2. W hat are the different ways in which individuals with a particular trait may increase in the population? 2 3. Why is DNA copying an essential part of the process of reproduction? Give two reasons. 2 4. How do Plasmodium and Leishmania reproduce? Write one difference in their mode of reproduction. 2 5. Draw a well labelled diagram of human female reproductive system. Explain the menstural cycle of female. 2 Or State the changes that take place in the uterus when: (a) Implantation of embryo has occurred. (b) Female gamete/egg is not fertilised. 6. (a) A positively charged particle (a-particle) projected towards west is deflected towards north by a magnetic 2 field. What is direction of the magnetic field? (b) State Fleming's left hand rule. Or (a) Which properties of proton can change when it moves in stronger magnetic field : mass, velocity, momentum? Give reason. (b) What is principle of electric motor? 2 7. Construct an aquatic food chain showing four trophic levels. Or What is meant by biodiversity? List two advantages of conserving forests and wild life. SECTION-B 8. Atom of an element contain six valence electrons. This element is present in air, about 21%. It exists as diatomic 3 molecule. (a) Identify the element. (b) Show the bond formed between two atoms of this element. (c) Write formula of compound of this element with carbon. Which is present in atmosphere? 3 9. (a) Do C3H6, C4H8, C5H10 belong to same or different homologous series? Give reason. Name the series. (b) Draw electron dot diagram of C2H2. (c) What is difference in structure of diamond and graphite? Or (a) Identify functional groups in following organic compounds. (i) CH3COCH2CH3 (ii) CH3CH2CH2CHO (iii) HCOOH (iv) CH3–CH2–OH (b) Why does carbon not form C4+ ions? 10. (a) A Mendelian experiment consisted of breading tall pea plants bearing violet flowers with short pea plant with white flowers. In the progeny all bore violet flowers, but almost half of them are short. How can we depict the 3 genetic make up of tall parent? 40
(b) What type of organs are our arm and a dog's fore leg? (c) A study found that children with light coloured eyes are likely to have parents with light coloured eyes. On this basis, can we say anything about whether light eye colour trait is dominant or recessive? Why or why not? 11. (a) State Ohm's law. 3 (b) Two lamps one rated 100W; 200V and other 60W: 220V are connected in parallel to main supply. Find the current drawn by two bulbs from the line if supply voltage is 220V. 12. Three resistors 2 W each A, B and C are connected as shown in figure. Each of them dissipates energy and can withstand a maximum power of 18 W without melting. Find the maximum current that can flow through the three resistors. 3 2Ω B I 2Ω A C 2Ω Or B1, B2 and B3 are three bulbs identical connected as shown in figure. When all the three bulbs glow, a current of 3A is recorded by ammeter ‘A’. A1 B1 B2 A2 A3 B3 +– • A 4.5V (a) What happens to the glow of the other two bulbs when the bulb B1 gets fused? 3 (b) What happens to the reading of A1, A2 and A3 and A when bulb B2 gets fused? (c) How much power is dissipated in the circuit when all the three bulbs glow together? 13. (a) What is meant by sustainable management? Why is reuse considered better than recycling? (b) Name any two items which can easily be recycled if cannot be used again. SECTION-C 14. Elements are arranged is Modern periodic table in increasing order of their atomic numbers. Metals are on left hand side an in the middle of periodic table mainly and non-metals are right hand side. A zig-zag diagonal line divides metals and non-metals. Elements of same group have same number of valence electrons but different number of shells. Elements in the middle of periodic table are called transition metals. 4 (a) Which element of Group 17 is most reactive and why? (1) (b) What is correct formula of hydride of nitrogen? (1) (c) Which group elements are soft, low melting and highly reactive metals. Give two metals whose density is less than that of water? (2) Practice Paper–9 n 41
Or Write the formula of (i) sulphate (ii) phosphate of Mg. 15. Mr. Ramesh took a coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder and passed electric current through it. The pattern of magnetic field line around a current carrying solenoid is shown in figure: 4 (a) Why are magnetic field produced by bar magnet and solenoid similar? (1) (b) What is form of magnetic field lines inside the solenoid? What does it indicate? (1) (c) How is electromagnet prepared? Explain. (2) Or Draw the magnetic field lines the field produced by a current carrying circular loop. 42 n Science– X
10Practice Paper– Time Allowed: 2 Hours Maximum Marks: 40 General Instructions: Same as Practice Paper-1. SECTION-A 1. What is the main difference between sperms and eggs of humans? Write the importance of this difference. 2 2. The chromosomal number of the sexually producing parents and their offspring is the same. Justify this statement. 2 3. How does equal genetic contribution of male and female parents ensured the progeny. 2 4. Explain how sexual reproduction gives rise to more viable variation than asexual reproduction. How does this 2 affect the evolution of these organisms that reproduce sexually? 5. Explain the terms analogous and homologous organs with example. 2 Or How did Mendel explain that it is possible that a trait is inherited but not expressed in an organism? 2 6. (a) When is force experienced by a current carrying conductor placed in magnetic field largest? (b) What happens to current at the time of short circuit? Or (a) Two circular coils A and B are placed close to each other. If current in the coil ‘A’ is changed, will some current be induced in the coil B? Give reason. (b) Define electromagnetic induction. 7. Pesticides are used in agriculture. How would it affect the trophic levels in the food chain associated having four 2 trophic levels? Justify your answer. Or In the following food chain, vertical arrows indicate the energy lost to the environment and horizontal arrows indicate energy transferred to next trophic level. Which one of three vertical arrows A, C, E and which one of the two A and D will represent more energy transfer? Give reason to your answer. A C D E Green plants B Goat Lion (Carnivores) (Producers) (Herbivores) SECTION-B 8. (a) Name one element which shows similar properties to chlorine. 3 (b) What is formula of hydride of sulphur? (c) Why are noble gases least reactive? Or (a) An element belongs to 3rd period and group 14. Identify the element and write its electronic configuration. (b) An element has one valence electron, belongs to first period. Identify the element. (c) 9 B belongs to which group and period? 5 43
9. (a) The electronic configuration of elements W, X,Y and Z are given below: 3 W 2, 1 X 2, 8, 8, 2 Y 2, 8, 5 Z 2, 8, 8 (i) Identify noble gas. (ii) Write the formula of compound formed by X and Y. (iii) What are valency of W and Z? 10. O utline a project which aims to find the dominant coat colour in dogs. 3 11. What is electrical resistivity? In a series of electric circuit comprising a resistor made up of metallic wire, the ammeter reads 5A. The reading of ammeter decreases to half when length of wire is doubled, why? 3 12. Find the current I in the circuit given below: 3 IA E 30Ω 3V 30Ω 15Ω B 15Ω C D Or A Bulb is rated as 200 V, 100 W. Calculate its resistance. Five such bulbs are lighted for 4 hours daily. Calculate the units of electrical energy consumed per day and what would be cost of using these bulbs per day at the rate of ` 4.00 per unit? 13. What are by-products of fertilizer industries? How do they affect the environment? How waste management should 3 be done in fertilizer industry? SECTION-C 14. Homologous series is series of organic compounds which have same functional group. Each homologous series has a general formula from which all members of family can be derived. Each successive member differ in CinHc2hienmteicraml sproofpneurmtiebseranodf asthoomws and 14u in terms of mass. Members of homologous series resemble gradation in physical properties. 4 (a) If formula of 10th member of a homologous series is C10H22, what will be formula of 5th member?(1) (b) What is formula of 3rd member of aldehyde homologous series? (1) (c) Write structural formula and electron dot structure of 1st member of carboxylic acid homologous series. (2) Or gCr3oHu6pOs is formula which represents two isomers. Write both the isomers and identify functional present in them. 15. Ohm’s law gives the relationship between current flowing through a conductor with potential difference across it, provided the physical conditions and temperature remains constant. The 44 n Science– X
electric current flowing in a circuit can be measured by an ammeter. Potential difference is measured by voltmeter connected in parallel to the battery or cell. Resistances can reduce current in the circuit. A variable resistor or rheostat is used to vary the current in the circuit. 4 (a) What type of conductor is represented by the following graph? (1) I (1) (2) V (b) What is slope of above graph equal to? (c) Name two factors on which resistors of conductor depends. Or What types of conductors are represented by graphs (i) and (ii)? I I V V (i) (ii) Practice Paper–10 n 45
11Practice Paper– (CBSE Sample Question Paper 2021-22) Time Allowed: 2 Hours Maximum Marks: 40 General Instructions: Same as Practice Paper-1. SECTION-A 1. The table shows the electronic structures of four elements. 2 2 Element Electronic Structure P 2,6 Q 2,8,1 R 2,8,7 S 2,8,8 (a) Identify which element(s) will form covalent bonds with carbon. (b) “Carbon reacts with an element in the above table to form several compounds.” Give suitable reason. 2. The diagram below shows part of the periodic table. (a) Which elements would react together to form covalent compounds? 2 (b) Between the two elements W and Z, which will have a bigger atomic radius? Why? 2 3. (a) Trace the path a male gamete takes to fertilise a female gamete after being released from the penis. (b) State the number of sets of chromosomes present in a zygote. 4. Rajesh observed a patch of greenish black powdery mass on a stale piece of bread. (a) Name the organism responsible for this and its specific mode of asexual reproduction. (b) Name its vegetative and reproductive parts. 5. Mustard was growing in two fields- A and B. While Field A produced brown coloured seeds, field B produced yellow coloured seeds. 2 It was observed that in field A, the offsprings showed only the parental trait for consecutive generations, whereas in field B, majority of the offsprings showed a variation in the progeny. What are the probable reasons for these? Or In an asexually reproducing species, if a trait X exists in 5% of a population and trait Y exists in 70% of the same population, which of the two trait is likely to have arisen earlier? Give reason. 6. A simple motor is made in a school laboratory. A coil of wire is mounted on an axle between the poles of a horseshoe magnet, as illustrated. 2 46
In the example above, coil ABCD is horizontal and the battery is connected as shown. (a) For this position, state the direction of the force on the arm AB. (b) Why does the current in the arm BC not contribute to the turning force on the coil? Or A circuit contains a battery, a variable resistor and a solenoid. The figure below shows the magnetic field pattern produced by the current in the solenoid. (a) State how the magnetic field pattern indicates regions where the magnetic field is stronger. (b) What happens to the magnetic field when the current in the circuit is reversed? 7. DDT was sprayed in a lake to regulate breeding of mosquitoes. How would it affect the trophic levels in the following food chain associated with a lake? Justify your answer. 2 Or In the following food chain, vertical arrows indicate the energy lost to the environment and horizontal arrows indicate energy transferred to the next trophic level. Which one of the three vertical arrows (A, C and E) and which one of the two horizontal arrows (B and D) will represent more energy transfer? Give reason for your answer. Practice Paper–11 n 47
SECTION-B 8. Choose an element from period 3 of modern periodic table that matches the description given below in each instance. Give reason for your choice. 3 (a) It has a similar structure to diamond. (b) It has same valency as lithium. (c) It has variable valency and is a member of the Oxygen family (group 16). 9. (a) How many isomers are possible for the compound with the molecular formula C4H8? Draw the electron dot 3 structure of branched chain isomer. (b) How will you prove that C4H8 and C5H10 are homologues? Or A carbon compound ‘A’ having melting point 156K and boiling point 351K, with molecular formula C2H6O is soluble in water in all proportions. (a) Identify ‘A’ and draw its electron dot structure. (b) Give the molecular formulae of any two homologues of ‘A’. 10. Two pea plants - one with round yellow seeds (RRYY) and another with wrinkled green (rryy) seeds produce F1 progeny that have round, yellow (RrYy) seeds. When F1 plants are self-pollinated, which new combination of characters is expected in F2 progeny? How many seeds with these new combinations of characters will be produced when a total 160 seeds are produced in F2 generation? Explain with reason. 3 11. (a) It would cost a man ` 3.50 to buy 1.0 kW h of electrical energy from the main electricity board. His 3 generator has a maximum power of 2.0 kW. The generator produces energy at this maximum power for 3 hours. Calculate how much it would cost to buy the same amount of energy from the main electricity board. (b) A student boils water in an electric kettle for 20 minutes. Using the same mains supply he wants to reduce the boiling time of water. To do so should he increase or decrease the length of the heating element? Justify your answer. 12. 3 In the above circuit, if the current reading in the ammeter A is 2A, what would be the value of R1? Or Calculate the total resistance of the circuit and find the total current in the circuit. 48 n Science– X
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