Question

The velocity of sound in air $360m{s}^{-1}$ while that in water is $1440m{s}^{-1}$ . If the wavelength of sound in air is 2 cm, that in water is

• A. $\frac{1}{2}cm$
• B. 2 cm
• C. 8 cm
• D. 16 cm

Answer 1

The correct option is C 8 cm

$V_S=360\left(air\right)=f\lambda$
$=\lambda =\frac{360}{f}=2\times {10}^{-2}\therefore f=180\times {10}^2$
Now $(V_s{)}_w=1440=f\lambda$
$1440=180\times {10}^2\times \lambda$
$\lambda =8cm$