202110244-TRIUMPH-STUDENT-WORKBOOK-PHYSICAL_SCIENCE-G09-PART2

AS7-Application to daily life, concern to bio diversity Short Answer Type Questions 21. Answer the following questions in 3-4 sentences. (i) [(Session 12.3)] What happens if we listen to loud music? (ii) [(Session 12.3)] What range of sound is considered normal to humans? CHAPTER 12. SOUND 99

22. Answer the following questions in 3-4 sentences. (i) [(Session 12.2)] On what properties does speed of a sound wave depend? (ii) [(Session 12.2)] What is sonic boom? How does it damage buildings? Long Answer Type Questions 23. Answer the following questions in 6-8 sentences. (i) [(Session 12.4)] How have ultrasonic waves helped doctors? Explain with the help of an example. CHAPTER 12. SOUND 100

24. Answer the following questions in 6-8 sentences. (i) [(Session 12.3)] You are going to design an auditorium. You have been told that you need to take care in avoiding reflection of sound waves. What would you do to minimize the reflection of sound waves? CHAPTER 12. SOUND 101

25. Answer the following questions in 6-8 sentences. (i) [(Session 12.2)] Why is the sound produced from a stretched string different, when it is plucked lightly than when plucked strongly? CHAPTER 12. SOUND 102

Objective Questions AS1-Conceptual Understanding 26. Choose the correct answer. (i) The SI unit of wavelength is (B) Metre (A) Centimetre (C) Pascal (D)kg/m 3 (ii) Maximum disturbance of the particles in the medium on either side of its mean position is called the (A) oscillation (B) frequency (C) dispersion (D) amplitude (iii) One megahertz (MHz) is equal to (B) 103 Hz (D)108 Hz (A) 102 Hz (C)106 Hz (B) electromagnetic in nature (iv) Sound waves are (A) transverse in nature (C)magnetic in nature (D)longitudinal in nature (v) The distance between two consecutive compressions or rarefactions is called (A) wavelength (B) amplitude (C) frequency (D)time period (vi) The number of oscillations completed in one second is called (A) amplitude (B) frequency (C) pitch (D) tone CHAPTER 12. SOUND 103

(vii) The range of audibility for human ears is (B) 20kHz –200 kHz (A) 2 Hz–20 kHz (C)2 kHz –20 kHz (D)20 Hz –20 kHz (viii) A reflection of sound, arriving at the listener in more than 0.1 s after direct sound is called (A) reverberation (B) echo (C) loudness (D) pitch AS2-Asking questions and making hypothesis 27. Choose the correct answer. (i) Which is the characteristic of sound that distinguishes between a shrill sound and a deep, low sound ? (A) Wavelength (B) Pitch (C)Time period (D) Frequency (ii) Sound wave of which frequency is an ultrasonic sound? (A) 300 Hz (B) 30 Hz (C)30,000 Hz (D)3000 Hz (iii) Which is the characteristic of sound that enables us to distinguish between musical notes emitted by different musical instruments? (A) Loudness (B) Quality (C) Pitch (D) Frequency AS4-Information skills and projects 28. Choose the correct answer. (i) The loudness of the sound is measured in CHAPTER 12. SOUND 104

(A) Hertz (B) Pascal (C) Decibel (D) Kilohertz AS5-Communication through drawing and model making 29. Choose the correct answer. (i) Identify the instrument shown in the following diagram. (A) SONAR (B) RADAR (C)Tuning fork (D) Stethoscope CHAPTER 12. SOUND 105

PROJECT BASED QUESTIONS —— Project Based Questions —— (i) Create a working model to show the functioning of a hydro electric power plant. (ii) Taking examples of dolphin and bat make a detailed report on how animals use echoes to locate objects or their prey. ( http://www.cyberphysics.co.uk/topics/waves/sound/echo.html ) (iii) Design the steps of an experiment to show that sound is a form of energy. Write in a science journal. Or Collect pictures of various kinds of musical instruments from internet and make a scrap book describing how do these instruments make sound. (iv) Research on why engineers need to know about the heat capacity of materials when designing equipment, structures and products and write a detailed report on it. Project Based Questions 106