On a slinky,we can produce:

What is an echo? When can we distinctly hear the echo of a sharp sound? Why cannot we hear an echo in small halls?

If the density of a medium through which sound is propagating is minimum,then this point is called:

If the frequency of a tuning fork is $400 \, Hz$ and the speed of sound in air is $340 \, m s^{-1}$,find how far sound travels when the tuning fork makes $16$ vibrations. (in $, m$)

Explain with the help of a diagram,how defects in a metal block can be detected using ultrasound.

Establish the relationship between the speed of sound, its wavelength, and frequency. If the velocity of sound in air is $340 \, m \, s^{-1}$, calculate:
$(i)$ The wavelength when the frequency is $256 \, Hz$.
$(ii)$ The frequency when the wavelength is $0.85 \, m$.