Question

For a wave displacement amplitude is 10^-8, density of air 1.3 kg / m^3 , velovity in the air 340 m/s anf frequency is 2000 hz . The intensity of wave is

Answer 1

Explanation :

It is given that,

Amplitude of the wave, $A=10^{-8}\ m$

Density of air, $\rho=1.3\ kg/m^3$

Velocity of air, $v=340\ m/s$

Frequency, $\nu=2000\ Hz$

The intensity of wave is given by the following relation :

$I=\dfrac{1}{2}\rho A^2\omega^2c$....................(1)

$\omega$ is angular frequency, $\omega=2\pi \nu$

c is the speed of light.

So, equation (1) becomes :

$I=\dfrac{1}{2}\times 1.3\ kg/m^3\times (10^{-8}\ m)^2\times (2\pi \times 2000\ Hz)^2 \times 3\times 10^8\ m/s$

$I=3.0761\ W/m^2$

Hence, this is the required solution.