Class-9 Science Chapter 12: Sound - Latest Prepared Assignments

Important Topics

• Nature of sound
• Propagation of sound in different media
• Speed of sound
• Reflection of sound and echo
• Structure of human ear and hearing mechanism

A. MCQs (1 mark each)

1. Sound is produced by:
   a) Light vibrations    b) Vibrating body    c) Static body    d) Force only
2. Which medium does sound travel fastest in?
   a) Air    b) Water    c) Steel    d) Vacuum
3. Echo is caused due to:
   a) Refraction of sound    b) Diffraction of sound    c) Reflection of sound    d) Absorption
4. Audible range of human hearing is approximately:
   a) 20 Hz – 20 kHz    b) 10 Hz – 10 kHz    c) 50 Hz – 15 kHz    d) 1 Hz – 100 kHz
5. In which of these does sound not travel?
   a) Air    b) Water    c) Steel    d) Vacuum

B. Short Answer Questions (2–3 marks)

1. Define sound and explain its characteristics.
2. Differentiate between loudness and pitch.
3. Calculate the time taken by sound to travel 1 km in air (speed = 343 m/s).
4. Explain echo and how it is formed.
5. Describe the structure of the human ear with a diagram.

C. Long Answer Questions (5 marks)

1. Explain the propagation of sound in solids, liquids, and gases.
2. Describe the working of the human ear and explain how we perceive sound.

D. Practical/Activity-Based Questions

1. Observe the vibration of a tuning fork in water and explain the production of sound.
2. Measure the speed of sound using echo method.