Question

⚫. ⚫. ⚫. ⚫. ⚫
A. S1. B. S2. C
In the figure shown, S1 and S2 represents two stationary sources of sound having equal
frequency, one observer is moving from A toward
C with velocity V° then -
(1) Beats for three position A, B and C will be
heard
(2) Beats will be heard from A and C but not in
case of B
(3) Beats will be not heard for A and C but will
be heard for B
(4) Beats will be not heard for three position of A, B and C​

Answer 1

$\huge\bigstar\underline\pink{Answer}$

★ At position A, observed frequencies of sound from both sources of sound is given as

fs1 = fs2 = [1+ (Vo/v)]fs

where,

Vo = velocity of observer

V = speed of sound

fs = actual frequency of sources S1 and S2

(Observer is moving towards both sources )

Since both observed frequencies are same beats will not be heard.

★ At position B, observed frequency of sound from source-1 is given as

fs1 = [1- (Vo /v)]fs

(Observer is moving away from Source S1)

★ At position B, observed frequency of sound from source-2 is given as

fs2 = [1+ (Vo / v)]fs

Since observed frequencies are slightly different (fs2> fs1), beats will be heard.

★ At position C, observed frequencies of sound from both sources of sound is given as

fs1 = fs2 = [1- (Vo/v)]fs

(Observer is moving away from both sources ) Since both observed frequencies are same beats will not be heard.

Option 3 is correct

☑️(3) Beats will not be heard at A and C, but will be heard at B

$\huge\red{\ddot{\smile}}$