The shape of the atomic structure can be found by ______.

Decreasing amplitude decreases _______.

• The amplitude of a vibrating body continuously decreases during damped vibrations.
• Because the frictional (resistive) force due to the surrounding medium causes the energy loss.

Which of the following parts acts as a passage for the sound waves into the ear?

Which of the following organs vibrate on encountering a sound?

• Ear pinna collects the sound and directs them into the ear.

Sound has shape.

Which organ in an animal ear collects the sound waves and directs them into the ear?

Communication in the submarines is using infra waves.

The unit of frequency is __________.

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

• The audible frequency range is 20Hz to 20KHz.
• The sound with frequencies less than 20Hz is called infrasound.

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.