Reflection of Sound

Q.

If a person drops a pebble in a well of $100m$ depth, after how much time (in seconds) will he be able to hear the sound?
Given:
Acceleration due to gravity, $g=10m{s}^{-2}$
Speed of sound in air, $v=343m{s}^{-1}$

1. $\sqrt{20}+0.3s$

2. $\sqrt{20}s$

3. $0.3s$

4. $20s$

Q. Ultrasound can be used for which of the following purposes?

1. Echocardiography
2. Ultrasonography
3. MRI scan
4. Loudspeakers

Q. Bats detect the obstacles in their path by detecting the reflected___.

1. Radio waves
2. Infrasonic waves
3. Electro-magnetic waves
4. Ultrasonic waves

Q. Compression is a region of:

1. Refraction of sound waves
2. Reflection of sound waves
3. Echo of the sounds
4. Absence of other sounds

Q.

For a sound wave, angle of reflection is always______angle of incidence.

1. twice the

2. less than

3. greater than

4. equal to

Q.

What frequency do whales communicate at ?

1. infrasonic frequencies as low as 5 Hz

2. ultrasonic frequencies as high as 45 kHz

3. in the audible range of the human ear

4. both A and B

Q.

Sound and light waves:

1. have similar wavelength

2. obey the laws of reflection

3. travel as longitudinal waves

4. travel through vacuum

Q.

This phenomenon reverberation can be observed in:

1. Auditoriums

2. Cinema halls

3. Indoor stadiums

4. All of these

Q.

The angle of reflection equals to the angle of incidence, only holds true for the light wave but not for a sound wave.

1. False

2. True

Q.

Bats produce high-pitched ultrasonic squeaks to know the distance of his prey.

1. True

2. False