Waves Ques 77
77. A source and an observer move away from each other, with a velocity of $10 $ $m / s$ with respect to ground. If the observer finds the frequency of sound coming from the source as $1950$ $ Hz$, then original frequency of source is (velocity of sound in air $=340$ $ m / s$ )
[2001]
(a) $1950 $ $Hz$
(b) $2068 $ $Hz$
(c) $2132 $ $Hz$
(d) $2486 $ $Hz$
Show Answer
Answer:
Correct Answer: 77.(b)
Solution:
- (b) According to Doppler’s effect
$ n^{\prime}=(\frac{v-v_0}{v-v_s}) n=(\frac{340-10}{340+10}) n=\frac{330}{350} \times 1950 $
$ =2068 $ $Hz $
BETA
