The sounds with frequencies greater than 20 kHz are called _____.

An increase in wavelength makes a sound wave _______.

• Sounds with frequencies below 20Hz are infrasound.
• Wave speed= frequency × wavelength 

Sound travels faster in _________ .

Sound cannot travel through _________.

A child was observing the thunderstorm from the glass window of his room. What would he feel first?

Sound with high frequency is called as   ________.

Sounds with frequencies less than 20Hz are called infrasound.

Metal cracks are detected using ________ sounds.

• Ultrasound or high frequency sound waves is transmitted into materials to characterize the material or for crack detection.

Animals like elephants communicate in _______ sounds.

Sound which has less frequency are called as ________ sounds

Sounds which have frequencies more than 20kHz are called ultrasounds.

A sound wave traveling at a speed of 1000 m/s has a frequency of 1 kHz. Its wavelength is ___ m.

2.5 kHz = ____ Hz.

In which of the following mediums does the sound propagate at the highest speed?

The picture below indicates a _____.

Shock waves carry ____.

The distance covered by a compression of a sound wave per unit time is _____.

A child was observing a thunderstorm from the glass window of his room. He hears thunder after seeing the lightning, even if these two events occur at the same time. This is because the speed of light ____ the speed of sound.