Ultrasound frequencies are ____ audible frequencies.

As we humans grow older, our ears become ______.

Elephants use _____ to communicate with each other.

• The infrasound frequencies are good for long distance communication because they travel well through objects instead of being reflected.

What does a hearing-impaired do to hear clearly?

When an ear drum encounters a sound it ____.

• Compression or high pressure pushes the eardrum inwards.
• Rarefaction or low pressure pulls the eardrum outwards.

The frequency of vibration of an object is 15000 Hz. A person ____ hear it.

Which of the following is a part of inner ear?

• Cochlea is an important organ for sound perception.

The frequency of vibration of an object is 15 Hz. A person ____ hear it.

• Sounds with frequencies below 20Hz are called infrasound.

When an ear drum encounters a compression, it ____.

• Rarefactions or low pressure pulls the eardrum outwards.

Frequency is denoted by _____.

• Wavelength is denoted by λ.
• Pronounced as lambda.

When the air pressure near the ear drum decreases, it ____.

• Compressions/high pressure pushes the eardrum inwards.

The conversion of the amplified pressure vibrations to electrical signals is done by _____.

• Auditory nerve transmits the signals from the internal ear (cochlea) to the brain.
• Ear ossicles amplify the sound.

The ear drum receives the sound in the form of ____.

The sounds with frequencies smaller than 20 Hz are called _____.

• Sounds with frequencies 20Hz to 20kHz are called audible frequencies.
• Sounds with frequencies more than 20Khz are called ultrasound.

The sonar can detect the enemy ship using _________.

Distance can be measured using ___________ .