wave_mechanics dopplers_effect Question 65
Question: An observer moves towards a stationary source of sound, with a velocity one-fifth of the velocity of sound. What is the percentage increase in the apparent frequency
[AIEEE 2005]
Options:
A) 5%
B) 20%
C) Zero
D) 0.5%
Show Answer
Answer:
Correct Answer: B
Solution:
When observer moves towards stationary source then apparent frequency $ n’=[ \frac{v+v _{O}}{v} ]n $
$ =[ \frac{v+v/5}{v} ]n $
$ =\frac{6}{5}n=1.2n $ Increment in frequency = 0.2 n so percentage change in frequency = $ \frac{0.2n}{n}\times 100 $ = 20%.
BETA
