A bat is flitting about in a cave, navigating via ultrasonic beeps. Assume that the sound emission frequency of the bat is 40 kHz. During one fast swoop directly toward a flat wall surface, the bat moves at 0.03 times the speed of sound in the air. What frequency does the bat hear reflected off the wall?

1. 41.27 kHz

2. 42.67 kHz

3. 41.23 kHz

4. 42.47 kHz

Which of the following phenomenon cannot take place with sound waves?

(1) Polarisation

(2) Refraction

(3) Diffraction

(4) Reflection

The speed of sound in air is independent of its:

(1) Amplitude

(2) Frequency

(3) Phase

(4) All of these

The waves which cannot travel without medium are:

(1) X-rays

(2) Radio waves

(3) Light waves

(4) Sound waves

When a wave propagating through a medium encounters a change in medium, then which of the following property remains the same?

(1) Speed

(2) Amplitude

(3) Frequency

(4) Wavelength

A transverse wave travels along the x-axis. The particles of medium move:

(1) Along the x-axis

(2) Along the y-axis

(3) Along the z-axis

(4) Either along the y-axis or z-axis

The phenomenon of sound propagation in the air is:

(1) An isothermal process

(2) An adiabatic process

(3) An isobaric process

(4) An isochoric process

If at STP, the velocity of sound in a gas $(\gamma =1.5)$ is 600 m/s, the RMS velocity of the gas molecules at STP will be:

(1) 400 m/s

(2) 600 m/s

(3) 600$\sqrt{2}$ m/s

(4) 300$\sqrt{2}$ m/s

In a stretched string:

(1) Only transverse waves can exist

(2) Only longitudinal waves can exist

(3) Both transverse and longitudinal waves can exist

(4) None of these

Two strings of the same material are stretched to the same tension. If their radii are in the ratio of 1: 2, then respective wave velocities in them will be in the ratio of:

(1) 4: 1

(2) 2: 1

(3) 1: 2

(4) 1: 4