Waves - Result Question 71
73. A speeding motorcyclist sees trafic jam ahead of him. He slows down to $36 km / hour$. He finds that traffic has eased and a car moving ahead of him at $18 km /$ hour is honking at a frequency of $1392 Hz$. If the speeds of sound is $343 m / s$, the frequency of the honk as heard by him will be :
[2014]
(a) $1332 Hz$
(b) $1372 Hz$
(c) $1412 Hz$
(d) $1464 Hz$
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Answer:
Correct Answer: 73. (c)
Solution:
- (c) According to Doppler’s effect Apparent frequency,
$n^{\prime}=n(\frac{v+v_0}{v+v_s})=1392(\frac{343+10}{343+5})$.
$=1412 Hz$
