Question

Dolphins emit clicks of sound for communication and echolocation. A marine biologist is monitoring a dolphin swimming in seawater where the speed of sound is 1520 m/s. When the dolphin is swimming directly away at 7.2 m/s, the marine biologist measures the number of clicks occuring per second to be at a frequency of 2210 Hz. What is the difference (in Hz) between this frequency and the number of clicks per second actually emitted by the dolphin?

Answer 1

Answer:

10 Hz.

Explanation:

v = Speed of sound in water = 1520 m/s

$v_s$= Speed of dolphin = 7.2 m/s

$f_s$= Frequency transmitted = 2210 Hz

Doppler effect

$f=\frac{v}{v+v_s}f_s\\\Rightarrow f=\frac{1520}{1520+7.2}2210\\\Rightarrow f=2199.58\ Hz$

$f_s-f=2210-2200 = 10 Hz$

∴ Difference (in Hz) between this frequency and the number of clicks per second actually emitted by the dolphin is 10 Hz.