The pulse rate of a man is $80$ beats in one minute. Calculate its frequency. (in $ Hz$)

Two musical notes of the same pitch and loudness are played on a violin and a piano. The waveforms are as shown in the figures below. Explain why the wave patterns are different.

State two practical uses or applications of echoes.

State whether the following waves are transverse or longitudinal waves :
$(i)$ light waves
$(ii)$ waves in water and
$(iii)$ sound waves.

Name the subjective property of sound related to its frequency and of light related to its wavelength.

State whether the following statement is true or false:
The frequency of a sounding body with a time period of $0.01 \, s$ is $100 \, Hz$.