Question

An ultrasound pulse has a wavelength of 1.0mm. Its speed in water is 1400m. What’s the frequency?

Answer 1

Answer:

$1.4\cdot 10^6 Hz$

Explanation:

The relationship between the frequency, the wavelength and the speed of a wave is given by the wave's equation:

$v=f \lambda$

where

v is the speed of the wave

f is the frequency

$\lambda$ is the wavelength

For the pulse in this problem,

$\lambda = 1.0 mm = 0.001 m\\v = 1400 m/s$

Solving for  f, we find the frequency:

$f=\frac{v}{\lambda}=\frac{1400}{0.001}=1.4\cdot 10^6 Hz$