Question

A source of sound is travelling with a velocity 40 km/h towards an observer and emits a sound of frequency 2000 Hz. If the velocity of sound is 1220 km/h, then the apparent frequency heard by the observer is _____.

Answer 1

A source of sound is travelling with a velocity 40 km/h towards an observer and emits a sound of frequency 2000 Hz. If the velocity of sound is 1220 km/h, then the apparent frequency heard by the observer is 2068 Hz.

Hint:
Apparent frequency heard by the observer.

Data:
v = 1220 km/h (or) 339 ms^-1
v_S = 40 km/h (or) 11.1 ms^-1
n = 2000 Hz

n' = `("v"/("v"-"v"_s))` n 

= `(339/(339-11.1))` x 2000

= 1.03385 x 2000
= n' = 2068 Hz.