Anita Paul, Seema Sinha, Deepika Parashari and, Karuni Subrahmanyam Solutions for Exercise 4: Put on your thinking cap

The _____ is a stretched membrane in ear, that vibrates on receiving sound vibrations.

The loudness of sound is expressed in _____.

Dolphins can hear sounds up to the frequency of _____ $\mathrm{Hz}$.

(Choose from $100 /1000/100000$)

Sound can propagate through gases and liquids but not solids.

Three vocal cords are stretched across the voice box.

The loudness of sound is proportional to the square of the amplitude of vibration producing the sound.

Sounds with frequencies greater than $20,000 \mathrm{Hz}$ are known as ultrasounds.

The normal conversation has a loudness of $30 \mathrm{dB}$.