202110728-PERFORM-STUDENT-WORKBOOK-SCIENCE-G10-FY_Optimized

PRACTICE SHEET - 4 (PS-4) 10. The correct increasing order of the atomic radii of the elements oxygen,fluorine, and nitrogen is a. O,F,N b. O,N,F c. N,F,O d. F,O,N II. Short Answer Questions. 1. State the Modern periodic law. Why is position assigned to hydrogen in Periodic table considered anomalous. 2. The elements of the third period of the periodic table are given below. Na, Mg, Al, Si, p, S, Cl, Ar Which atom is bigger Na or Mg? Why? Identify the most metallic and most non metallic element. 3. A metal ‘X’ forms an oxide having the formula XO. It belongs to third period in the modern periodic table. Write the atomic number, valency, electronic configuration and name of the group to which the element belongs.(A) III. Long Answer Questions. 1. Write in detail how Mendeleev's Classified the elements. Elaborate on the achievements and limitations of Mendeleev's periodic table. (R) 2. Observe the given table and answer the following questions. (A) 1 2 13 14 15 16 17 18 Lithium X Carbon Oxygen L Neon Y Z SP Q R T i) Which is the most reactive metal? ii) Name the family of L, Q, R, T iii) Name one element of group 2 and 15 iv)Name one member of group 18 other than neon. v) Give the name of the element S placed below Carbon. in group 14 37

SELF-EVALUATION SHEET Marks: 15 Time: 30 Mins I. Choose the most appropriate word: IV. Answer each of these questions: (2 Marks) 1. Write the advantages and limitations of the 1. Non-metals are found on the _____ side of the Mendeleev's model. periodic table towards the top. (3 Marks) a. Left hand b. Right hand c. Middle 2. According to the modern periodic law, properties of elements are a periodic function of their________ a. Atomic weight b. Atomic number c. Valency d. none of the above II. Give one-word answer for the followings: (3 Marks) 1. The atomic mass of nitrogen. 2. Elements with similar chemical properties but 2. How were the limitations of the previous different atomic masses. tables resolved by the modern periodic table? (3 Marks) 3. The vertical columns in the periodic table. III. State whether the following statements are true or false: (4 Marks) 1. Henry Moseley designed a new periodic table called the modern periodic table. 2. In modern periodic table there are 18 vertical columns known as groups and 18 horizontal rows known as periods. 3. It was found that the Law of Octaves was applicable only up to calcium, as after calcium every eighth element did not possess properties similar to that of the first. 4. In Mendeleev's model isotopes are perfectly placed. 38

6. Life Processes Learning Outcomes At the end of this lesson, students will be able to: • Explain the process of photosynthesis and • Explain various types of nutrition i.e. respiration in plants. autotrophic, hetrotrophic and saprophytic • List out the components of human blood and nutrition state its importance. • Explain structure and functions of each organ • Explain the working of human heart. in the human digestive system • Explain transportation of food and water in • Differentiate between aerobic and anaerobic plants. respiration • Explain structure and function of each organ in • Explain structure and function of each organ in the human excretory system. the human respiratory system. • Explain the process of excretion in plants. Concept Map Life processes Nutrition Respiration Transportation Excretion  Autotrophic Human respiratory  Human heart  Excretion in human nutrition system  Human beings  Heterotrophic circulatory  Excretion in plants nutrition system  Blood and its  Human digestive components system Key Points that are aerobic and anaerobic • Human respiratory system consists of the nose, • Nutrition is the process of obtaining nutrients from the environment i.e. intake of food and pharynx, trachea, bronchi, bronchioles and al- then its digestion in the body. veoli. • Double circulation occurs in human beings i.e. • Two types – Autotrophic (self-sufficient for food) the blood goes through the heart twice during and Heterotrophic (dependent on others for each cardiac cycle. food). • Blood and lymph are both involved in transpor- tation. • Synthesis of food by photosynthesis ‘photo’ • Components of blood are RBCs, WBCs, plate- means light and ‘synthesis’ means production. lets, and plasma. It is the production of food with the help of sun- • Three types of blood vessels are arteries, veins light. and capillaries. • Transportation of water is through xylem tis- • Human digestive system- consists of the long sues. alimentary canal that includes mouth, pharynx, • Transport of food or translocation takes place oesophagus, stomach, small intestine, large in- through phloem and it requires energy. testine, rectum and anus. Liver, pancreas and • Excretion is the process of removal of harmful gall bladder also play an important role in the metabolic wastes from the body of organisms process of digestion. 39 • Respiration is the process which is controlled by enzymes and energy is released from the break- down of organic substances. It is of two types

6. Life Processes by various processes. • The excretory system consists of- a pair of kidneys, a pair of ureters, a urinary bladder, and a urethra. • Key Words – nutrition, respiration, pharynx, oe- sophagus, stomach, small intestine, large intes- tine, rectum, liver, pancreas, gall bladder, trachea, bronchi, bronchioles, alveoli, lymph, nephron, xylem, phloem, stomata, plasma, platelets, arteries, veins, kidney, ureter, urethra Work Plan CONCEPT COVERAGE COVERAGE DETAILS PRACTICE SHEET SIMULATION/ Nutrition • Autotrophic nutrition PS-1 VIDEO Respiration • Heterotrophic nutrition PS-2 Transportation • Human digestive system PS -3 Autotrophic Nutri- Excretion • Digestion of food in PS-4 tion human beings Human Alimentary • Anaerobic respiration Canal • Aerobic respiration • Human respiratory Human Respiratory System system • Human heart Liberation of CO2 • Human circulatory during respiration system Liberation of • Components of blood CO2 during • Transportation in plants fermentation Human Heart through xylem and Human Excretory phloem • Human excretory system System • Structure of nephron • Excretion in plants Worksheet for \"Life Processes\" PS-5 Evaluation with self- check Self-evaluation or Peer check* Sheet 40

PRACTICE SHEET - 1 (PS-1) III.  Write one function of the following. 1. Salivary amylase I.  Multiple choice questions. 2. Pepsin 3. Trypsin 1. Proteins after digestion are converted into 4. Lipase a. Carbohydrates b. Small globules   c. Amino acids d. Starch 2. The small pores present of leaf’s surface are called a. Stomata b. Chlorophyll c. Guard cells d. None of these 3. Opening and closing of pores is a function per- formed by a. Stomata b. Chlorophyll c. Chloroplast d. Guard cells 4. Which element is used in the synthesis of pro- teins? a. Hydrogen b. Oxygen c. Nitrogen d. Carbon dioxide II.  Answer each of these questions. 1. List out the events that occur during photosyn- thesis. 2. A polyethene bag was tied to the leaves as shown in the picture given below. What would you observe after some time, and why? 3. How do guard cells prevent excessive loss of water from the leaves? 4. How does amoeba take and digest food? 41

PRACTICE SHEET - 2 (PS-2) I.  Label the parts 1 to 7 in the given diagram. II.  Answer each of these questions. 1. Write the differences between aerobic and an- aerobic respiration. 2. Observe the diagram and explain why lime wa- ter turns milky? 3. Why does sudden activity give us muscle cramps? 4. How does respiration occur in fishes? 5. What is the purpose of mucus and the fine pair in our nostrils? 6. Give the formulaic representation of how glu- cose breaks down due to lack of oxygen. 42

PRACTICE SHEET - 3 (PS-3) I.  Multiple choice questions. 1. How many chambers are present in human heart? a. 2 b. 3 c. 4 d. 6 2. In which part of the body does blood get puri- fied (becomes oxygenated)? a. Heart b. Lungs c. Atrium d. Ventricle 3. The loss of water in the form of vapours from the aerial parts of a plant is known as_____. a. Translocation b. Evaporation c. Expiration d. Transpiration 4. Transportation of food from leaves to other parts of the plant is called________. a. Translocation b. Transpiration c. Ascent d. Translation 5. Oxygenated blood from left ventricle is distrib- uted to other parts of the body through_____. a. Vena cava b. Pulmonary artery c. Pulmonary vein d. Aorta II.  Answer these questions. 1. How does translocation occur in plants? 2. Write the function of lymph. 3. Why do arteries have thick elastic walls? 4. How does circulation happen in fish? 5. What is double circulation? 6. Why do veins have valves? 7. Usually injury leads to bleeding. What would happen in case of an heart injury and the bleed- ing does not stop? 43

PRACTICE SHEET - 4 (PS-4) I. Draw a diagram of human excretory system and label renal artery and urethra. State in brief the function of: Kidney Ureter Urinary bladder II.  Answer these questions. 1. Which is the filtration unit of kidney? 2. How does excretion occur in plants? 3. Name the organs of human excretory system, 4. What happens to glucose that enters the neph- ron along with filtrate? 5. How is urine produced and eliminated? 6. Why are we able to control the urge to urinate? 44

PRACTICE SHEET - 5 (PS-5) I. Choose the correct option. 1. The process by which organisms obtain energy to maintain function of life, to build matter is a. Respiration b. Digestion c. Nutrition d. Excretion 2. Translocation of food occurs through: a. Xylem b. Epidermis c. Phloem d. Cortex 3. Enzyme present in saliva a. Lipase b. Pepsin c. Ptyalin d. Trypsin 4. Dialysing fluid is similar to osmotic pressure of blood except that a. It is devoid of Glucose. b. It is devoid of amino acids. c. It is devoid of platelets. d. It is devoid of nitrogenous waste. 5. These structures of the heart control the direction of the flow of blood. a. Right atrium b. Veins c. Left atrium d. Valves 6. The water which is lost through transpiration in leaf is replaced by a. Phloem vessels in the leaf b. Xylem vessels in the leaf c. Sieve cells d. Companion cells 7. A leaf is boiled in alcohol before using Iodine for starch test in order to: a. Soften the leaf b. Dissolve starch c. Dissolve chlorophyll d. Make it react with Iodine 8. While playing Ria got wounded and blood was oozing out. Which of the following will be in the first place to help recovery from the injury? a. Red blood cells b. White blood cells c. Platelets d. Lymph 45

PRACTICE SHEET - 5 (PS-5) 9. Given below are the steps to be followed for performing ‘starch test’ on a green leaf. i.Boil the leaf in Alcohol ii.Boil the leaf in water iii.Dip the leaf in Iodine iv.Wash the leaf in water Pick the correct sequence to be followed for correct result. a. i,iv,ii,iii b. iv,i,ii,iii c. ii,iv,i,iii d. ii,i,iv,iii 10. The instrument that a doctor uses to measure a systolic and diastolic pressure. a. Anemometer b. Stethoscope c. Sphygmomanometer d. Electrocardiogram II. Short Answer Questions. 1. Write about the importance of lymph in our body. 2. Write the type of respiration that has the following end products. Give an example for each where such respiration occurs. i. Lactic acid ii.CO2 and H2O iii. C2H5OH and CO2 3. Simple diffusion meets the oxygen requirement in Unicellular organisms. This is not possible in multicellu- lar organisms. What structures helps to fulfill the oxygen requirements in them. Explain. III. Long Answer Questions. 1. Describe with a diagram, how pseudopodia helps in nutrition in Amoeba. 2. Draw a neat labelled diagram of the internal structure of the blood pumping organ in our body. 46

SELF-EVALUATION SHEET Marks: 15 Time: 30 Mins I.  Answer each of these in one or two words: 2. Justify the following statements: i. The nostril passage has a lining of mucus. (3 Marks) ii. Rings of cartilage are present in the trachea. iii. Alveoli contains an extensive network of 1. Which metal is associated with the formation of blood vessels. haemoglobin? 2. Which organ secretes bile juice? 3. Name a three carbon compound formed during the process of respiration. II.  Answer each of these in about 20-30 words. (6 Marks) 1. Why is the process of transpiration essential to the plants? IV. Answer this question in about 70 words. (5 Marks) 2. Why do the walls of the trachea not collapse 1. Explain the step-wise blood circulation in the when there is less air in it? human body through the heart. 3. Why is the rate of breathing in aquatic organ- isms much faster than in terrestrial organisms? III. Answer each of these in about 40-50 words. (6 Marks) 1. State three points of differences between arteries and veins. 47

Control and Coordination Learning Outcomes • Explain the source of function of hormones. • State the disorders caused due to At the end of this lesson, students will be able to: • Explain the structure of neuron. malfunctioning of hormones. • Explain reflex action. • Explain the control and coordination in plants. • Differentiate between nervous control and • Describe various tropic movements in plants. • State the importance of various plant chemical control. • Explain the structure of brain. hormones. • Explain the functions of each part of brain. Concept Map Control and coordination Nervous system in animals Coordination in plants • Reflex action • Response to stimulus • Human brain • Movement due to growth • Hormones in animals Key Points • The working together of various organs of the body cals (At synapse). of an organism in a proper manner to produce ap- • Reflex action is the spontaneous, involuntary and propriate reaction to a stimulus is called coordina- automatic response to a stimulus to protect us from tion. harmful situations. • The changes in the environment to which an organ- • Reflex arc is the pathway of the reflex action. ism responds and reacts is called Stimulus. • Nervous system is of two types - Central Nervous • Control & coordination in animals- takes place by (i) system (CNS) and Peripheral Nervous system (PNS). Nervous system & (ii) Endocrine system. • Hormones are the chemical messengers sent by the • Parts of the Nervous system are brain, Spinal cord glands. and Nerves (Neurons). • The movements of plants in the direction of stim- • A Neuron is the structural & functional unit of Ner- ulus (positive) or away from it (negative) are called vous system. tropic movements. E.g. Phototropism, Geotro- • Parts of a neuron are Dendrites, Cell body and Axon pism.,Chemotropism. • Synapse is Space/junction between two adjacent Key Words – Reflex, Neuron, tropism, impulse, ner- nerves. vous system, hormones, endocrine gland. • Passing of information takes place (i) By Electric im- pulse (inside the neuron) (ii) In the form of chemi- 48

Control and Coordination Work Plan CONCEPT COVERAGE COVERAGE DETAILS PRACTICE SHEET Simulation/ Video Reflex action • Structure of neuron PS-1 • Reflex arc PS-2 Neuron • Reflex action Reflex Arc PS-3 Human Brain Human brain • Parts of human brain Phototropism • Functions of each part of PS-4 Geotropism PS-5 Endocrine System human brain Self-evaluation Sheet Coordination in plants • Response to stimuli • Tropism (hydrotropism, chemotropism and geotropism) • Functions of plant hormones. Hormones in animals • Adrenaline • Thyroxine • Insulin • Growth hormone • Source of these hormone. • Diseases caused due to malfunction of these hormones Worksheet for \"Control and Coordination\" Evaluation with self- check or Peer check* 49

PRACTICE SHEET - 1 (PS-1) I.  Draw a neat labelled diagram showing the structure of neuron. II.  Name the following. 1. The receptors that detect taste. 2. The receptors that detect smell. 3. A sudden response to something in the environment. 4. The site where reflex action is formed. III.  Define these terms. 1. Synapse 2. Reflex arc IV.  Answer each of these questions. 1. In a neuron cell, how is an electrical impulse created and what is the role of synapse in this context? 2. Why have reflex arcs evolved in animals? PRACTICE SHEET - 2 (PS-2) I. Draw a neat labelled diagram of human brain. II. Write the functions of each of these parts of the brain - Medulla. Cerebellum. III. Answer these questions. 1. How is brain protected? 2. Name the three main regions of human brain. 3. Why is fore brain called as main thinking part of the brain? 4. How do muscles change their shape and size when an electric impulse is received? PRACTICE SHEET - 3 (PS-3) I.  Name the hormones based on the description given a) Stimulates growth of the stem. b) Stimulates growth of the shoot tip. c) Promotes cell division. d) Inhibits growth. II.  Write one example of these types of tropism a. Chemotropism b. Geotropism c. Phototropism III.  Answer each of these questions 1. Why do tendrils circle around the object near them? 2. What is hydro-tropism? 3. Write any one effect of presence of abscisic acid in the plants. 4. What are the disadvantages of electrical impulses as a medium of control and coordination? 50

PRACTICE SHEET - 4 (PS-4) I.  Fill in the blanks. 1. Diabetes is caused due to under secretion of ________________. 2. ___________________ is caused due to under secretion of thyroxine. 3. Growth hormone is secreted by _________________ gland. 4. __________________ is the male sex hormone. 5. _________________ is the female sex hormone. 6. ________________ gland is the master gland of the human body. II.  Write the functions of 1. Thyroxine 2. Insulin. 3. Growth hormone III.  Answer these questions. 1. How does adrenaline hormone work in emergency situations? 2. The timing and amount of hormone released, are regulated by the feedback mechanisms. Give one exam- ple of such feedback mechanism. 51

PRACTICE SHEET - 5 (PS-5) I. Choose the correct option. 1. Signals of endocrine system are a. Electric impulse b. Neuron c. Hormone d. Brain 2. Choose the incorrect statement related to reflex arc. a. Reflex arcs are formed in the brain. b. Reflex arcs are formed in spinal cord. c. Reflex arcs evolved as an efficient way of functioning. d. Reflex arcs connections are made between the input nerve and the output nerve. 3. Persons suffering from diabetes may take injections of a. Iodine b. Insulin c. Protein d. Glucose 4. Identify the hormone that inhibits plant growth. a. Auxin b. Cytokinin c. Gibberellins d. Abscisic acid 5. Gustatory receptors sense a. touch b. taste c. smell d. Pressure 6.The region where the nerve endings of one neuron comes in contact with another neuron is a. Receptor b. Synapse c. Terminal d. Effector 7. Ria while attending a food mela, happened to cross a chinese food stall. Her mouth watered due to the typical chinese aroma. Pick the part of the brain controls this behaviour. a. Hypothalamus b. Medulla of the hind brain c. Pituitary gland d. Fore brain 8. While plucking rose flower from the plant, a thorn pricked her finger. She would respond immediately to the situation through a a. Nastic movement b. Reflex action c. Voluntary action d. Chemotropic movement 52

PRACTICE SHEET - 6 (PS-6) 9. Hormone ‘X’ is released in an emergency situation of freight or flight from gland ‘Y’. Which among the following controls the gland ‘Y’. a. Pituitary gland b. Thyroid gland c. Pancreas d. Adrenal gland 10. Deficiency of this mineral in the diet would lead to a disease called ‘Goitre’. a. Sodium b. Chlorine c. Iodine d. Potassium II. Short Answer Questions. 1. Name and write the functions of the phytohormones that helps plant growth. 2. Label the parts from i. to vi. in the human brain. 3. A structure ‘A’ is a functional part of the brain, that has three parts. Part ‘X’ which receives the information that travels through part ’Y’ and then to part ‘Z’ in the form of ‘E’ which gets converted into chemical signal near the part Z. Identify and write A, X, Y and Z and E. Name the structure formed between the two ‘A’ for further information transmission. III. Long Answer Questions. 1. Define and explain in detail Tropism and its types in plants. 2. Draw a neat labelled diagram of human brain. Write the function of any five parts of brain. 53

SELF-EVALUATION SHEET Marks: 20 Time: 30 Mins I.  Answer each of these in one word: (3 Marks) IV. Answer this question in about 70 words. 1. Name the hormone secreted by the ovaries. (5 Marks) 2. Which mineral helps in production of thyroxine? 1. Write any five points of difference between nervous control and chemical control. 3. Under-secretion of which hormone causes dwarfism? II.  Answer each of these in about 20-30 words. (6 Marks) 1. Explain how auxins help in bending of plant stem towards light. 2. Where are reflex arcs formed? Why? 3. In which part of the plant - stem or fruits will the concentration of cytokinins will be more and why? III.  Answer each of these in about 40-50 words. (6 Marks) 1. i.  Label the parts (a), (b), (c) and (d) in the fol- lowing figure. ii.  Which part of the nervous system facilitates the communication between the central ner- vous system and the other parts of the body? 2. Blood test report of George showed certain ab- normalities. Based on the blood test report the doctor suggested a low sugar diet. i. Which disease George is suffering from? ii. How is such an abnormality caused? 54

8. How do Organisms Reproduce? Learning Outcomes self-pollination. • Explain the structure and function of various At the end of this lesson, students will be able to: • State the importance of reproduction. organs of human male and female reproductive • Differentiate between asexual and sexual repro- system. • Explain menstrual cycle. duction. • Explain the process of feotus formation in human • Explain various modes of asexual reproduction beings. • Elaborate the importance of safe sexual inter- - fission, fragmentation, regeneration, budding, course. vegetative propagation and spore formation. • Explain the sexual reproduction in plants. • Differentiate between cross pollination and Concept Map How do animals reproduce Asexual reproduction Sexual reproduction Reproductive health • Fission Sexual reprobdeuincgtison in human Sexual reproduction in plants • Budding • Vegetative propagation • Regeneration • Fragmentation • Spore formation Key Points involvement of gametes or sex cells. • However, in sexual reproduction, the offspring • Production of new organisms from existing organisms of the same species is known as arises from two parents of different sexes, by reproduction. DNA plays an important role combination of their gametes. in this, because chromosomes present in the • Main parts of a flower are sepals, petals, stamens nucleus of a cell contain information to be and carpel. Out of this, stamen and carpel are transferred to the offspring, in the form of DNA. the reproductive parts. • Ovary contains ovule – each ovule has an egg • This DNA in cell nucleus is the information cell source for making proteins, which perform a lot • Fusion of this female egg cell with male egg cell of important functions in our body. gives the zygote, which eventually gives rise to • In asexual mode of reproduction, the offspring 55 arises from a single parent, without the

8. How do Organisms Reproduce? a new plant. This process of fusion is called fertilization. • After fertilization, zygote undergoes repeated division to form an embryo. The ovule is finally converted into a seed. It contains the future plant, which develops under suitable conditions and the process is called germination. • The human male reproductive system consists of testes, vas deferns and penis. • The human female reproductive system consists of ovaries, fallopean tubes, uterus, cervix and vagina. • The male and female gametes fuse together, and the fertilised egg, the zygote, gets implanted in the lining of the uterus, and starts dividing. • The embryo gets nutrition from the mother’s blood with the help of a special tissue called placenta. It provides a large surface area for glucose and oxygen to pass from the mother to the embryo and waste substances to pass from embryo to mother. • The child develops inside the mother’s body and is born as a result of rhythmic contractions of the muscles in the uterus. • Under some circumstances, pregancy could be unwanted or undesired. Methods such as using condoms, copper-T or intaking contraceptive pills can prevent pregnancy. • Surgical methods can also be used to terminate pregnancices. 56

8. How do Organisms Reproduce? Work Plan CONCEPT COVERAGE COVERAGE DETAILS PRACTICE SHEET Asexual • Importance of reproduction PS-1 reproduction • Variation between parents and their progeny • Fission PS-2 • Fragmentation • Regeneration PS-3 • Budding PS-4 • Spore formation Self-evaluation • Vegetative propagation Sheet Sexual • Benefits of sexual mode of reproduction. reproduction in plants • Parts of a flower • Vegetative and reproductive parts of a flower • Unisexual and bisexual flower • Types of pollination • Fertilzation and zygote formation • Germination Sexual reproduction in • Changes in the human body during adoloscence human beings • Male reproductive system • Female reproductive system • Menstrual cycle • Importance of safe sexual intercourse • Sexually transmitted diseases • Methods to prevent and terminate preganancy. Worksheet for \"How do Organisms Reproduce\"? Evaluation with self- check or peer check 57

PRACTICE SHEET - 1 (PS-1) I. Fill in the blanks: 1. The chromosomes in the nucleus of a cell contain information for inheritance of features from parents to next generation in the form of _____. 2. Kala-azar disease is caused by ____. 3. In hydra, _____ develop into tiny individuals and then fully mature. 4. The parasite that causes malaria is ____. II. Answer each of these questions: 1. Explain binary fission as a way of reproduction with an example and a neat diagram. 2. Roopa collected a water sample from a pond. She observed some dark green filamentous structures in the sample of water. What are these structures and how do they reproduce? 3. Explain two ways by which hydra can reproduce. 4. Which are the non-reproductive and reproductive parts of rhizopus? 5. How does bryophyllum reproduce? List our other examples which reproduce in a similar manner. PRACTICE SHEET - 2 (PS-2) I. Fill in the blanks: 1. Stamen is the male reproductive part and it produces _______ that are yellowish in colour. 2. _______ is present in the centre of a flower and is the female reproductive part. 3. Indetify the parts labelled A, B and C. II. Refer to the picture given in the previous question, and name the part which: a. stores food b. is a future root c. is a future shoot. III. Answer each of these questions: 1. Draw a neat labelled diagram of longitudinal section of a bisexual flower. 2. Explain the female reproductive parts of flower. 3. How is a zygote formed in a flower? 4. What is the difference between self pollination and cross pollination? 5. List out the changes that occur in a flower after fertilisation. 6. What is germination? 58

PRACTICE SHEET - 3 (PS-3) I. Fill in the blanks to complete the paragraph: When a girl is born, the ovaries already contain thousands of immature eggs. On reaching puberty, some of these start maturing. One egg is produced every month by one of the ovaries. The egg is carried from the ovary to the womb through a thin ___(1) into an elastic bag-like structure known as the ____(2). The formation of sperms takes place in the ____(3). These are located outside the abdominal cavity in ____(4). The sperms formed are delivered through the ___(5) which unites with a tube coming from the _____(6). II. Answer each of these questions: 1. What are the functions of testosterone? 2. Explain the process of zygote formation in human beings. 3. Explain the structure and function of placenta. 4. Unwanted pregnancies can be terminated through surgerical methods. What could be the wrong implication of this method? 5. What are the side-effects of using copper-T? 6. List out the sexually transmitted diseases. 59

PRACTICE SHEET - 4 (PS-4) I. Choose the correct option. 1. Hydra can reproduce a. By budding only b. By regeneration only c. By budding and regeneration d. By fragmentation only 2. The surgical method of contraception in males consists of ligating of a. Epididymis b. Urethra c. Vas deferens d. Vas efferentia 3. In human females, an event that reflects onset of reproductive phase is: a. Changes in hair pattern b. Change in Voice c. Growth of body d. Menstruation 4. In this plant, a piece of leaf can regenerate the whole plant. a. Rose b. Banana c. Hibiscus d. Bryophyllum 5. Reproduction is essential for the a. Maintenance of an individual b. Extinction of any species c. Creation of a species d. Perpetuation of any species 6. In spirogyra, asexual reproduction takes place by: a. Division of a cell into many cells. b. Breaking up of filaments into smaller bits. c. Division of a cell into two cells. d. Formation of young cells from older cells. 7. In the given diagram, identify the correct labels for A, B and C a . A-cotyledon, B-Plumule, C-radicle b. A-cotyledon, B - Radicle, C-Plumule c. A- Embryo, B-Cotyledon, C-Plumule d. A - Cotyledon , B-Embryo, C-Plumule 8.Fusion of male and female gamete results in the formation of a. Embryo b. Foetus c. Zygote d. Ovum 9. Identify the incorrect statement: a. Ovary develops into the seed and ovule into fruit. b. Ovule develops into seed and ovary into the fruit. c. Seed contains the future plant. d. Petals, sepals, stamen and style fall off after formation of fruit. 60

PRACTICE SHEET - 4 (PS-4) 10 .The flowchart represent the correct sequence for the occurrence of menstruation in human females a. b. c. d. II. Short Answer Questions. 1. In what ways does sexual reproduction differs from asexual one? State at least three reasons. 2. Write the full form of DNA. Name the part of the cell where it is located. Explain its role in the process of reproduction of the cell. 3. Explain budding in Hydra with a suitable diagram. III. Long Answer Questions. 1. List the reasons for adopting contraceptive methods. Explain different methods of contraception. 2. Explain in detail the formation of fruit from ovary. Include a note on types of pollination. 61

SELF-EVALUATION SHEET Marks: 15 Time: 30 Mins I. Name the mode of reproduction in each of these organisms: (4 Marks) 2. Multicellular organisms cannot reproduce through fragmentation. Explain the statement. a. Planaria (3 Marks) b. Plasmodium c. Ginger d. Fungus II. Answer each of these questions: 1. What happens when the egg is not fertilized? (5 Marks) 3. In what way is vegetative propagation an advantageous method of reproduction? (3 Marks) 62

9. Heredity and Evolution Learning Outcomes • Describe evolution with appropriate illustration. • Define speciation and factors affecting specia- At the end of this lesson, students will be able to: • State the importance of reproduction. tion. • Explain the accumulation of variation during • Explain the process of fossil formation. • Differentiate between homologouus and analo- reproduction. • Define heredity. gous organs with examples. • Classify the traits as inherited and acquired. • Explain the method for estimating the age of • State the Mendel’s rule of inheritance. • Explain the steps, observation and results of fossils. • Describe the human evolution. Mendel’s experiment on the pea plant. • Describe the sex determination in various organ- isms. Concept Map Heredity and Evolution Heredity Chemical Symbol and Formulae Evolution Speciation Fossil Key Points • Heredity means the transmission of features/ father will be a girl, and one who inherits a Y characters/ traits from one generation to the chromosome from him will be a boy. next generation. • In some animals the temperature at which the fertilised eggs are kept decides the gender. • Variation refers to the differences among the • Genetic drift leads to diversity without any individuals of a species/ population. adaptation. • Acquired traits are developed in an individual • Production of new organisms from existing due to special conditions. organisms of the same species is known as • Inherited traits are passed from one generation reproduction. DNA plays an important role to the next. in this, because chromosomes present in the • Micro evolution is the evolution which is on a nucleus of a cell contains information to be small scale. eg. change in body colour of beetles. transferred to the offspring, in the form of DNA. • Speciation is the process of formation of new species. • This DNA in cell nucleus is the information • Species is a group of similar individuals that source for making proteins, which perform a lot of important functions in our body. 63 • Mendel started his work on the pea plant. • A child who inherits an X chromosome from her

9. Heredity and Evolution Keywords – variation, DNA, speciation, evolution, fossils, traits. belong to a population that can interbreed and produce off spring. • Geneflow is the exchange of genetic material by interbreeding between populations of same species or individuals. • Both evolution and classification are interlinked. • Similarities among organisms allow us to group them together and to study their characteristic. 64

9. Heredity and Evolution Work Plan CONCEPT COVERAGE COVERAGE DETAILS PRACTICE SHEET PS-1 Variation during • Accumulation of variation during reproduc- reproduction, Heredity tion PS-2 Evolution and speciation • Heredity PS-3 Evolution and • Rules of inheritance PS-4 classification • How do traits get expressed Self-evaluation Sheet • Sex determination • Evolution • Acquired and inherited traits • Speciation • Factors affecting speciation • Classification • Tracing evolutionary relationships • Fossils • Evolution by stages • Human evolution Worksheet for \"Heredity and Evolution\" Evaluation with self- check or Peer check* 65

PRACTICE SHEET - 1 (PS-1) I. State whether each of these statements are true or false. 1. In the Mendel’s experiment, F1 generation of pea plants had all medium length plants. 2. Cellular DNA is the information source for making proteins in the cell. 3. When two germ cells combine, the normal number of chromosomes in the progeny will reduce. II. Answer each of these questions: 1. What do you mean by the term heredity? 2. State the rules of inheritance. 3. Which are the two types of traits seen in human beings with respect to the ear lobes? 4. How do proteins control the characteristics? Explain using plant tallness as an example. 5. Is it right to say that the baby’s gender is dependant on its mother? Explain your answer. PRACTICE SHEET - 2 (PS-2) I. Answer each of these questions: 1. What do you mean by the term evolution? 2. Explain acquired and inherited trait with an example of beetle weight. 3. There is an inbuilt tendency to variation during reproduction. What are the reasons for this variation? 4. A very small population of a species faces a greater threat of extinction than a larger population. Provide a suitable genetic explanation. 5. Explain the term micro-evolution. 6. List out the factors that lead to speciation. PRACTICE SHEET - 3 (PS-3) I. Answer each of these questions: 1. What is meant by the term characteristics? 2. Explain the meaning of homologous organs with an example. 3. Explain the meaning of analogous organs with an exmaple. 4. How are fossils formed? 5. Give an instance to say that birds are closely related to reptiles. 6. List out all the variations derived from the wild cabbage. 7. Why should we not equate evolution with progress? 66

PRACTICE SHEET - 4 (PS-4) 1. Bacteria can inhabit the most inhospitable habitats. It means, bacteria can be found in a. Hot springs b. Deep sea thermal vents c. Ice in Antarctica d. All the above 2. Number of chromosomes in human beings a. 23 b. 23 pairs c. 24 d. 24 pairs 3. The chromosome combination found in a human male is a. XX b. XY c. YY d. AY 4. Sexual reproduction and error in DNA copying leads to a. Speciation b. Variation c. Inheritance d. Elimination 5. Wild cabbage has evolved into new varieties by a. Natural selection b. Artificial selection c. Genetic drift d. Reproductive isolation 6. A trait in an organism is influenced by a. Paternal DNA only b. Maternal DNA only c. Both Maternal and Paternal DNA d. Neither paternal nor Maternal DNA 7. Identify the inherited trait among the following. a. Low weight due to starvation b. Loss of body parts in accident c. Height of the individual d. Body growth due to exercise 8. In Reptiles, the temperature at which fertilised eggs are kept determines whether the animals developing in the eggs will be male or female. This means that a. Sex of the offspring is not always genetically determined. b. Sex of the offspring is genetically determined. c. Sex of the offspring is totally dependent on the Female. d. Sex of the offspring is totally dependent on the Male. 9. Small changes in the population over a few generations that does not result in evolution. a. Macroevolution b. Microevolution c. Genetic drift d. Speciation 67

PRACTICE SHEET - 4 (PS-4) 10. Genetic drift may affect a. Gene mutation b. Gene expression c. Gene inheritance d. Gene Variation II. Short Answer Questions. 1. Explain Genetic drift. 2. Consider the two traits i) Fused and free ear lobes and ii) Muscular body of wrestler. Are they inherited or acquired traits? Why? 3. What is a gene? How does it work? III. Long Answer Questions. 1. Explain with a flowchart the sex determination in Humans. Who decides the sex of the unborn baby? Father or Mother? What is the probability that the unborn child is a girl or a boy? 2. Homologous organs are evidence of evolutionary relationship. Explain in detail. 68

SELF-EVALUATION SHEET Marks: 15 Time: 30 Mins I. Choose the most appropriate alternative for each of these statements: (4 Marks) 2. Write examples to show that sex determination 1. Which section of DNA provides information for is not genetic. (3 Marks) one protein? a. Nucleus b. Chromosomes c. Trait d. Gene 2. Which one is a possible progeny in F2 generation of pure bred tall plant with round seed and short plant with wrinkled seeds? a. Tall plant with round seeds b. Tall plant with wrinkled seeds c. Short plant with round seed d. All of the above 3. Homologous organs have 3. Explain the mechanism of inheritance of a. Same structure, same function b. Different structure, different function c. Same structure, different function d. different structure, same function characters. (3 Marks) 4. What is the probability that the male progeny will be a boy? a. 50% b. 56% c. 47.43% d. It varies II. Answer each of these questions: 1. Describe the method to determine the age of fossil. (5 marks) 69

10. Light-Reflection and Refraction Learning Outcomes • Compare refractive indices of the various medium. At the end of this lesson, students will be able to: • Define reflection and refraction • Explain refraction through a glass slab and • State the laws of reflection lens. • Differentiate between convex and concave • Represent images formed by lens using ray mirror diagrams • Represent images formed by spherical mirrors • Calculate focal length, image distance and using ray diagrams object distance using the lens formula. • Uses of convex and concave mirror • Calculate focal length, image distance and • Calculate the magnification and power of the lens object distance using the mirror formula. • Calculate the magnification of mirror • Use appropriate sign convention. • Define refraction. • List out the uses of lenses. • State the laws of refraction. Concept Map Light Reflection of Light Spherical Mirror Refraction of Light Spherical Lens Convex Mirror Convex Lens Concave Mirror Concave Lens Key Points • A negative sign in the value of the magnification indicates that the image is real. A positive sign • Laws of reflection – (i) The angle of incidence is in the value of the magnification indicates that equal to the angle of reflection. (ii)The incident the image is virtual. ray, the normal to the mirror at the point of in- cidence and the reflected ray, all lie in the same • Refraction of light is the bending of a ray of light plane. when it enters a medium where its speed is dif- ferent. The refraction of light when it passes • A spherical mirror, whose reflecting surface is from a fast medium to a slow medium, bends curved inwards, that is, faces towards the cen- the light ray toward the normal to the boundary tre of the sphere, is called a concave mirror. A between the two media. spherical mirror whose reflecting surface is curved outwards, is called a convex mirror. • The following are the laws of refraction of light- (i)The incident ray, the refracted ray and the • The centre of the reflecting surface of a spheri- normal to the interface of two transparent me- cal mirror is a point called the pole. dia at the point of incidence, all lie in the same plane.(ii)The ratio of sine of angle of incidence • The radius of curvature is found to be equal to twice the focal length. • The mirror formula is expressed as: • Magnification produced by a spherical mirror gives the relative extent to which the image of an object is magnified with respect to the object size. 70

10. Light-Reflection and Refraction its power. The power of a lens is defined as the reciprocal of its focal length. P= 1/f to the sine of angle of refraction is a constant, • The SI unit of power of a lens is ‘dioptre’. It is for the light of a given colour and for the given denoted by the letter D. pair of media. • The refractive index is the relative speed of propagation of light in different media. • The lens formula is expressed as: 1/v-1/u=1/f • The degree of convergence or divergence of light rays achieved by a lens is expressed in terms of Work Plan CONCEPT COVERAGE COVERAGE DETAILS PRACTICE SIMULATION/ SHEET VIDEO Reflection of light • Reflection of light PS-1 And • Laws of reflection Spherical mirror • Convex and concave mirrors • Image formed by spherical mirrors • Representation of images formed by spherical mirrors • Uses of convex and concave mirror Spherical mirror • Sign convention for reflection by PS-2 Video/ Simulation spherical mirror PS -3 Focal length of concave mirror • Mirror formula and magnification Image Formation Refraction of light • Refraction of light by concave Mirror Refraction by spherical • Laws of refraction Refraction through lenses • Refractive index a rectangular glass • Refraction through rectangular slab slab Focal length of • Refraction by spherical lenses • Image formed by spherical lenses convex lens • Ray diagrams Image formation by • Sign convention for refraction by convex Lens lenses • Lens formula PS-4 • Magnification • Power of a lens Wroksheet for \" Light, Reflection and Refractions\" PS-5 Evaluation with self- Self- check or Peer check* evaluation Sheet 71

PRACTICE SHEET - 1 (PS-1) 3. List out the uses of concave mirrors. I.  Choose the correct alternatives to complete the IV.  Complete the following table. sentences. Position of Position of Size of the im- 1. Angle of incidence and angle of reflection are the object the image age ____. At infinity At focus (i) a. equal Between F Beyond C (ii) b. unequal and C c. coherent At C At C (iii) d. Opposite 2. Phenomenon in which light travelling in one medium falls on surface of another medium and turns back in same medium is called a. Refraction of light b. Reflection of light c. Bending of light d. Diffraction of light 3. The center of reflecting surface of a spherical mirror is called _____. a. Focal length b. Pole c. Centre of curvature d. Aperture 4. The point where all the reflected rays meet are called ____. a. Focal length b. Pole c. Principal focus d. Aperture 5. An imaginary line that passes through the pole and centre of curvature of a spherical mirror is called ____. a. Focal length b. Pole c. Principal focus d. Principal axis II.  Define these terms 1. Focal length 2. Aperture 3. Spherical mirrors III.  Answer these questions: 1. A steel spoon or a steel plate can depict concave as well as convex mirror, Explain your answer. 2. Centre of curvature of a convex mirror is 15 cm. What would be its focal length? 72

PRACTICE SHEET - 2 (PS-2) I.  State whether the following statements are true or false. 1. The object is always placed to the left of the mirror. 2. All the distances parallel to principal axis are measured from the aperture of the mirror. 3. Distances measured perpendicular to and above the principal axis are taken as negative. 4. A positive sign in the value of the magnification indicates that the image is virtual. II.  Solve these. 1. When an object is placed at a distance of 60cm from a convex mirror, the magnification pro- duced is 1. Where should the objects be placed to get a magnification of 1/3? 2. A pencil 3 cm high is held at a distance of 50cm from a diverging mirror of focal length 25 cm. Find the nature, position, and size of the image formed. 3. An object is placed 10 cm from a concave mir- ror. The focal length is 5 cm. Determine (a) The image distance (b) the magnification of image. 4. A 2 cm high object is placed 7.10 cm from a con- cave mirror whose radius of curvature is 10.20 cm. Find the location of the image and its size. 5. A concave mirror of focal length 20cm is placed 50 cm from a wall. How far from the wall, an ob- ject be placed to form its real image on the wall? 6. An object is placed at distance of 25 cm from a spherical mirror and its image is formed behind the mirror at distance of 5 cm. Find focal length. Is it concave or convex mirror? 73

PRACTICE SHEET - 3 (PS-3) I.  Choose the correct alternatives to complete the sentences. 1. When a ray of light enters a denser medium, it: a. bends away from normal b. bends towards normal c. goes straight d. reflects back 2. The highest refractive index is found is ____. a. water b. glass c. diamond d. alcohol 3. The speed of light is maximum in ___. a. oil b. vacuum c. water d. glass 4. A light ray does not bend at the boundary in passing from one medium to another if the an- gle of incidence is _____. a. 45ᵒ b. 90ᵒ c. 0ᵒ d. 30ᵒ II.  Answer each of these questions: 1. State the laws of refraction of light. 2. What is meant by refractive index? 3. What is a lens? 4. Why do lens have two principal foci? 5. A concave mirror is held over a piece of paper in the bright sunlight. It is held such that a spot of light focuses on the paper. The paper eventually burns, why? III.  Solve these. 1. The speed of light in air is 3x10⁸ m/s and in glass 2x10⁸ m/s. Calculate its refractive index. 2. The refractive index of water is 4/3 and glass is 3. What is the refractive index of glass with re- spect to water? 74

PRACTICE SHEET - 4 (PS-4) I. Complete the following table. Types of lens Position of the Position of the Size of the object object image (i) Point sized Concave At infinity (ii) At 2F2 Highly enlarged Convex At 2F2 (iii) (iv) Convex At F1 Concave Between infinity and Between focus and optical centre optical centre II.  State whether the following statements are true or false. 1. A concave lens, if kept at a proper distance, can form a real image. 2. A ray of light incident at the optical centre of lens, passes undeviated after refraction. III.  Complete the paragraph by filling in the blanks: 1. Power is the reciprocal of ____(i) . Its SI unit is ____(ii). The power of convex lens is ___(iii) and concave lens is ____(iv). IV.  Solve these. 1. An object of height 4 cm is placed at a distance 24 cm in front of a convex lens of focal length 8 cm. Find the position and size of the image. 2. The focal length of a camera lens is 20 cm. How far the film must be taken in order to photo- graph an object located at a distance 100 cm from the lens. 75

PRACTICE SHEET - 5 (PS-5) I. Choose the correct option. 1. The branch of physics that deals with the study of light is called a. Astrology B. Physiology C. Phoenics D. Optics 2. The center of reflecting surface of spherical mirror is A. Radius B. Curvature C. Pole D. Vertex 3. The line passing through the pole and centre of curvature of spherical mirror. This line is called A. Pole B. Principle line C. Radius D. Line of curvature 4. What does 'f' denote in the given picture? a. Focal length b. Radius c. Principle line d. Pole 5. An object becomes invisible when it undergoes X reflection. Which reflection is X here? a. Normal b. Irregular c. Diffused d. Regular 6. A light ray can get reflected a. Multiple times b. Single time c. Two times d. Light ray is only absorbed 76

PRACTICE SHEET - 5 (PS-5) 7. Imagine when an object is placed at infinity position, what will be the size of image formed in a convex mirror? a. Clear b. Highly diminished c. Clean and vivid d. Image is not formed 8. Ria has taken a concave mirror, she placed an object between principal focus (F) and the pole (P). Help her to know what is X and Y in the given table. Position of the image Size of the image Nature of the image Object between P and F X Y a. X- Normal ; Y- Real b. X- Enlarged ; Y- Virtual c. X- Diminished ; Y- Virtual d. X- No image; Y- No image 9. Light travels in different media. The increasing order according to the speed of light is a. Glass> Air > Vacuum b. Air> Glass> Vacuum c. Vacuum> Air> Glass d. Vacuum>Glass> Air 10. The relationship between focal length and radius of curvature is a. R+2 = f b. R= f/2 c. f= R/2 d. f= 2 R II. Short Answer Questions. 1. Define Refraction of light. What is Snell' s law? 2. An object is placed at a distance of 30cm in front of a concave mirror of focal length is 10 cms. Calculate the distance of the image from the mirror and nature of the image. 3. What is the importance of lenses? How are they used in our daily life? III. Long Answer Questions. 1. Draw the ray diagram in each case to show position and nature of image formed in each case when the object. ( R) i. At the center of curvature of the concave mirror ii. Between the pole P and focus F of a concave mirror iii. In front of convex mirror iv. At infinity for concave mirror v. Give two uses of concave and convex mirrors each of which we use in our daily life. 2. Solve the following questions: i. An object is placed at infinite distance in front of convex mirror of radius of curvature 20 cms. How far is the image behind the mirror? ii. An object X is placed in front of a concave mirror with a focal length of 40 cms. The image formed is three times the size of X. Calculate the possible distances of X from the mirror. 77

SELF-EVALUATION SHEET Marks: 20 Time: 30 Mins I.  Answer each of these in one or two words: (3 Marks) 1. Which mirror is used in torch lights? 2. Name the lens which has a negative value for 2. The refractive indices of four media A, B, C and power. D are given in the following table: Medium A B C D 3. What is the central point of the lens is called? Refractive index 1.33 1.50 1.52 2.40 If light, travels from one medium to another, in II.  Answer each of these in about 20-30 words. which case the change in speed will be (i) mini- mum, (ii) maximum? Justify your answer. (6 Marks) 1. Why are large concave mirrors used in solar fur- naces? 2. Can a concave lens form an image of size two IV. Answer these question in about 70 words. times that of the object? Give reason for your answer. (5 Marks) 3. The height of an object is 5 cm and the magnifi- 3. (a) If the image formed by a lens is diminished cation of the image produced by a convex mir- in size and erect, for all positions of the object, ror is 0.6 cm. Find the height of the image. what type of lens is it? (b) Name the point on the lens through which a ray of light passes without deviating. (c) An object is placed perpendicular to the prin- cipal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm. Find (i) the position (ii) the magnification and (iii) the nature of the image formed. III.  Answer each of these in about 40-50 words. (6 Marks) 1. Draw a neat labeled diagram to show the for- mation of an image when an object is placed between F1 and 2F1 by a convex lens. What is the nature of the image formed? 78

11. The Human Eye and the Colourful World Learning Outcomes prism. • Describe the atmospheric refraction and its appli- At the end of this lesson, students will be able to: • Describe the parts of human eye. cations. • Explain the power of accommodation. • Explain the scattering light and its effects. • Explain the defects in eye and how to correct it. • Explain the refraction phenomenon. • Explain the refraction of white light through Concept Map The Human Eye and the Colourful World Human Eye Properties of Light Spectrum of Light Atmosphereic Refraction Key Points Effects • Human eyes are sensitive organs and it depending on the distance of the image enables us to see the beautiful world. Human that should be viewed. The ability of the eye is like a camera. It forms images on a light eye lens to adjust its focal length is called screen called retina. accommodation. • The minimum distance at which our eyes sees • The image is formed due to the various without any strain is called the least distance mechanisms in our eye. of vision. It is called the near point of the eye. • The crystalline of lens of old age people • Human eye consists of various parts due becomes white and cloudy called cataract. to which an image is formed on the retina. This causes the permanent or partial damage Retina is a delicate membrane having to the human eye and should be restored enormous light sensitive parts. Damage to or through surgery. malfunction of any part of usual visual system • For the perfect view, two eyes are required. can lead to significant loss of visual functions. Each eye sees a slightly separate image but • The eye lens consists of a fibrous jelly 79 like material. It can change its curvature

11. The Human Eye and the Colourful World our brain combines them and makes it as particles like smoke, water droplets, one image. Through both eye, 3 dimensional suspended particles and air. When light as well as a wide range of view is possible. strikes such particles the path of the beam • Sometimes, eye gradually loses its power of becomes visible. The striking of the light to accommodation and vision becomes blurred various particles is called as Tyndall effect. due to the refractive defects in the eye. • Depending on the size of scattering the light • Myopia or near sightedness, hypermetropia also varies, if size of the scattering particle is or far sightedness and presbyopia are the large enough then white light is observed. common defects that can be corrected by • Scattering light is more in shorter wave length using suitable lens. i e blue light. Hence, in the atmosphere the • Near sightedness is the case when a person fine particles in the air passes through the can see nearby objects clearly but cannot see blue colour more strongly than red. The red distant objects properly. This defect can be is least scattered by smoke or fog. corrected by using a concave lens of suitable • At noon, there will be little scattering hence power. sun appears white in colour. But near the • Hypermetropia is a case of far sightedness, horizon most of the blue light and shorter where a person can see far objects clearly wavelengths are scattered away by the but cannot see nearby objects distinctly. This particles hence longer light reaches our eyes. defect can be corrected by using a convex So, it gives the reddish appearance. lens of appropriate power. • Presbyopia is the case where power Keywords – Eyes, vision, diffraction, decreases as the age increases. They find scattering, defects in eye, prism, refraction, difficult to see nearby objects comfortably accommodation, refraction. without glasses. It can be corrected by using bifocal lens which consist of concave and convex. • About 35 million people are blind and we can donate our eyes and their blindness can be cured. • The peculiar shape of the prism makes the emergent ray bend at an angle to the direction of the incident ray. This is called the angle of deviation. • When white light incident on the prism it splits the light into different colors. The light splits in the order as follows Violet, Indigo, Blue, Green, Yellow, Orange and Red (VIBGYOR). The splitting of the color is known as dispersion. • Newton conducted an experiment on the spectrum and concluded that white light is made up of seven different colours. Rainbow is a natural spectrum appearing in the sky after a rain shower. • Due to the density difference and because of low density of the hot air, the refraction occurs and wavering effect of objects is observed. This is known as natural atmospheric refraction. Due to this phenomenon the twinkling of stars can also be seen. • The sun appears to us before 2 minutes to sunrise and 2 minutes after the actual sunset because of atmospheric refraction. • Due to scattering of light we can see different wonderful effects like blue colour sky, blue colour water, sunrise and sunsets etc. • The earth’s atmosphere consists of different 80

11. The Human Eye and the Colourful World Work Plan CONCEPT COVERAGE COVERAGE DETAILS PRACTICE SHEET Parts of human eye • Parts of human eye PS-1 • Power of accomodation PS-2 Defects in vision and corrections • Myopia • Hypermetropia PS-3 • Presbyopia PS-4 Refraction and other principles of • Refraction of the light through a prism PS-5 the light • Dispersion of light by a glass prism Self-evaluation Sheet • Atmospheric refraction Scattering of light • Tyndall effect • Reason for blue sky • Colours at sunrise and sunset Worksheet for \"Human Eye and the Colorful World\" Evaluation with self- check or peer check 81

PRACTICE SHEET - 1 (PS-1) I. Answer each of these questions: 1. Explain the parts of human eye with its functions. 2. What is the power of accommodation? 3. What is the least distance of vision? 4. What is cataract? How it can be cured? 5. Fill in the blanks: a. Light enters through a thin membrane called________. b. The structure behind the cornea is called_______. c. The _____of an eye acts like a variable aperture whose size can be varied with the help of iris. d. The minimum distance through which our eye can see without strain from the eye is _______ cm. 6. How does eye adjust depending on the distance of the object? PRACTICE SHEET - 2 (PS-2) I. Answer each of these questions: 1. What are the three main defects of vision? 2. Explain myopia and state how can it be rectified. 3. Explain hypermetropia and state how can it be rectified. 4. What is presbyopia? How can it be cured? 5. Choose the inappropriate statement. a. In a myopic eye, the image of a distant object is formed in front of the retina. b. Hypermetropia is may due to the too much small eyeball. c. The convex lens is used to cure the hypermetropia. 6. State whether the following statements are true or false. a. These days, it is possible to correct the refractive defects with contact lenses or through surgical interventions. b. Bifocal lens is required for a person who suffers from shortsightedness. 7. Match the followings: Defect Reason 1.Myopia a. The eyeball has be- come too small 2. Hypermetropia b. Gradual weakening of the ciliary muscles 3.Presbyopia c. Elongation of the eye- ball 82

PRACTICE SHEET - 3 (PS-3) 1. Explain the refraction of light through prism. 2. Explain the dispersion of white light by a glass prism. 3. Explain Newton’s experiment on dispersion of light. 4. What are the different colours obtained after the dispersion of the white light? 5. Why are different colours obtained after passing white light through prism? 6. State whether the following statements are true or false. a. A rainbow is a natural spectrum appearing in the sky after a rain shower. b. Any light that gives a spectrum similar to that of sunlight is often referred to as white light. c. The order of the colours after dispersion are violet, yellow, indigo, blue, green, orange and red. 7. Identify the following when light is incident on the triangular prism with respect to the following figure. i. PE ii. EF iii. FS iv. A v. i vi. r vii. e viii. D PRACTICE SHEET - 4 (PS-4) 1. Explain how twinkling of stars takes place? 2. What is the reason for the advanced sunrise and delayed sunset? 3. Fill in the blanks: a. The least scattered light is ____. b. The wavelength of the red light ______ times higher than the blue light. c. The phenomenon of scattering of light by the colloidal particle give rise to ________ effect. 4. State whether the following statements are true or false. a. The colour of the scattered light depends on the size of the scattering particles. b. Sun appears white as only a little of the blue and violet colours are scattered. 5. Why does the colour of the sun appears red during the sunset? 6. What are the different effects created by the natural refraction? 7. Why is the colour of sky blue? 83

PRACTICE SHEET - 5 (PS-5) I. Choose the correct option. 1. The human eye forms the image of an object at its a. Retina b. Pupil c. Cornea d. Iris 2. The crystalline lens of people at old age becomes milky and cloudy. This condition is a. Xerophthalmia b. Cataract c. Myopia d. Hypermetropia 3. Which phenomenon of light is responsible for working of eye? a. Reflection b. Attractiona c. Refraction d. Repulsion 4. The first scientist to use glass prism to obtain spectrum of sunlight. a. Faraday b. Fleming c. Lena d. Newton 5. When sunlight passes through a canopy of dense forest, this effect can be observed a. Spectrum b. Tyndall c. Photogenic d. All the above 6. Major part of refraction for light rays entering the eye occurs at a. Iris b. Pupil c. Cornea d. Lens 7. Eye lens forms a a. Virtual erect image b. Virtual diminished image c. No image d. Real and inverted image 8. The white part of the eye is P. The coloured part of the eye is Q. Find P and Q. a. P- Retina ; Q- Cornea b. P- Pupil ; Q- Cornea c. P- Iris ; Q- Sclera d. P - Sclera ; Q- Iris 9. When ciliary muscles are relaxed, the lens become thinner. What happens to focal length? a. Increases b. Decreases c. Remains same d. Decreases 4 times 84

PRACTICE SHEET - 5 (PS-5) 10. Here are some statements about presbyopia. Which among the following are true? a. It happens due to aging b. It happens due to decrease in flexibility of eye lens c. It happens due to gradual weakening of ciliary muscles d. All the above II. Short Answer Questions. 1. Answer the following questions. i. Arrange the scrambled words in order. • AOMYPI • TARCAATC • SGIMATISTM • ATINRE • RGYOIBV ii. Mention the functions of pupil, retina, ciliary muscles, iris. 2. Give reasons for following questions. i. Why the sky appears dark instead of blue to the astronaut? ii. Why planets have dimmer effect and do not twinkle? iii. Does focal length of human eye changes? Why? 3. Explain Tyndall effect with two examples. III. Long Answer Questions. 1. Draw a neat labelled diagram of the human eye. 2. Answer the following questions. i. When a Holi fire is set, you can observe random or flickering of the objects near a fire. Why? ii. An eleven year old girl cannot see a black board at 5 m distance. What may be the reason for that? How can we correct it? Represent the correction by ray diagram. iii. When we are out of dark room why can't we see things clearly for sometime? 85

SELF-EVALUATION SHEET Marks: 15 Time: 30 Mins I. Choose the most appropriate word: IV. Answer each of these question: 1. Explain the defects in vision and which lens (2 Marks) can be used to cure it. (3 Marks) 1. The scattering of the light is more effective in ______. a. Red light b. Blue light c. Visible light d. None of the above. 2. Light enters our eyes through ______. a. Pupil b. Retina c. Cornea d. none of the above II. State following statements are true or false: (3 Marks) 1. The eye forms an inverted real image of the object on the retina. 2. Eye cannot adjust for the longer and shorter objects. 3. Visible light consists of 5 different colours. III. Fill in the blanks: 2. Explain the dispersion of the light through a (4 Marks) glass prism. (3 Marks) 1. The least scattered light is =______. 2. The peculiar shape of the prism makes the emergent ray bend at an angle to the direction of the _____. 3. The prism has probably split the incident white in to band of colors. The band of colours is called ______. 4. Red lights are used as signal lights in smoke or fog. 86