An object, moving in a straight line with velocity 100 ms-1, goes past a stationary observer. If the object emits note of 400 Hz while moving, the change in the frequency note by the observer as the object goes past him is (speed of sound in air = 300 ms-1)

Question

An object, moving in a straight line with velocity 100 ms-1, goes past a stationary observer. If the object emits note of 400 Hz while moving, the change in the frequency note by the observer as the object goes past him is (speed of sound in air = 300 ms-1) (A) 350 Hz (B) 300 Hz (C) 200 Hz (D) 100 Hz

Tardigrade Admin · Accepted Answer

Given f=400 H2 ; c=300 m / s, v=100 m / c Let f1 and f2 are the frequencies observed before and after train passes the observer. Then, f1=f (C/C-v)=400 × (300/200)=600 H 2 f2=f (C/c+v)=400 × (300/400)=300 H 2 ∴ Δ f=f1-f2=300 Hz

Q. An object, moving in a straight line with velocity $100 m s^{- 1}$ , goes past a stationary observer. If the object emits note of $400 Hz$ while moving, the change in the frequency note by the observer as the object goes past him is
(speed of sound in air $= 300 m s^{- 1})$

$350 Hz$

$300 Hz$

$200 Hz$

$100 Hz$

$150 Hz$

Q. An object, moving in a straight line with velocity 100ms−1, goes past a stationary observer. If the object emits note of 400Hz while moving, the change in the frequency note by the observer as the object goes past him is (speed of sound in air =300ms−1)

350Hz

300Hz

200Hz

100Hz

150Hz