Available Answers

1. 1.

   Choose and write the correct answer(MCQs):

   1. The amplitude of the sound wave decides its:
      1. speed
      2. loudness
      3. source
      4. pitch
   2. The real organ of hearing in the human ear is the:
      1. ear drum
      2. cochelea
      3. oval window
      4. the 3 soft bones
   3. Sound waves travel fastest in:
      1. air 
      2. vacuum
      3. metals
      4. liquids 
   4. The minimum distance required to produce a distinct echo is:
      1. 15 m
      2. 10 m
      3. 11 m
      4. 17 m
2. 2.

   Fill in the blanks:

   1. Sound is caused by _________.
   2. Sound cannot travel through __________.
   3. The number of vibrations per second defines_________.
   4. The S.I unit of frequency is __________.
   5. Quality depends on number of ___________ of different relative loudness.
   6. Echoes are caused by the ___________ of the sound.
   7. Pitch depends on _________ of the sound.
   8. Time taken to complete one oscillation is the ___________.
3. 3.

   Write T for true or F for false:

   1. 1 hertz means 1 vibration per second.
   2. Excessive noise can cause deafness.
   3. Sound cannot travel through vacuum.
   4. A smooth plastered wall is a bad reflector of sound.
   5. The loudness of a sound depends on its frequency.
   6. Sound with frequency above 20,000 Hz is called infrasonics.
4. 4.

   Match the column A with column B:

   A	B
   1. Low frequency sound which we cannot hear	a. Hertz
   2. Instrument producing sound of single frequency	b. Tuning fork
   3. Unit of frequency	c. Infrasonics
   4. Maximum displacement of an oscillating objects	d. Amplitude
   5. Sound with a frequency of more than 20,000 Hz	e. Ultrasonic

    

5. 5.

   What are echoes and how are they produced?

6. 6.

   What are the uses of sound?