A traffic policeman standing on a road sounds a whistle emitting the main frequency of 2.00 kHz. What could be the apparent frequency heard by a scooter-driver approaching the policeman at a speed of 36.0 km/h? Speed of sound in air = 344) m/s.

Question

Philoid · Accepted Answer

2.06 Hz

As a consequence of Doppler effect the frequency heard will be changed. This can be calculated by the expression,

Here,

v = 340 ms^-1.

v₀=36kmh^-1 = 10 ms^-1.

f₀ = 2KHz

Feeding the values we get,