Before playing the orchestra in a musical concert,a sitarist tries to adjust the tension and pluck the string suitably. By doing so,he is adjusting

In the bell jar experiment,as air is removed from the jar,

$A$ laboratory uses an ultrasonic scanner to trace a tumour in tissue. The operating frequency of the scanner is $4.2 \times 10^{6} \text{ Hz}$. Calculate the wavelength of sound in the tissue if the speed of the sound is $1700 \text{ m s}^{-1}$.

Draw a labelled diagram of the auditory parts of the human ear and explain how the human ear works.

Why can we hear echoes in long galleries and big halls?

$(a)$ Write two points of difference between sound wave and light wave.
$(b)$ Write an expression relating wave velocity, wavelength and frequency if speed of sound in air is $340 \, m s^{-1}$.
Calculate:
$(i)$ Wavelength when frequency $= 256 \, Hz$.
$(ii)$ Frequency when wavelength $= 0.85 \, m$.