Question

A sound wave of length 45 um travels with a speed of 1800 m/s in a metallic medium. Find the frequency of the sound wave.

● none

● 15x 10^6Hz

● 40x10^3Hz

● 40x10^6Hz

Answer 1

Hi there!

We can use the following equation:

$\large\boxed{v = \lambda f}$

v = velocity of wave (m/s)
λ = wavelength (μm)

f = frequency (Hz)

We can rearrange the equation to solve for frequency:
$\large\boxed{f = \frac{v}{\lambda}}$

Plug in the givens. Make sure to convert μm to m:

1 μm = 0.000001 m

$f = \frac{1800}{0.000045} = 40000000 Hz = \boxed{40 \cdot 10^6 Hz}$