wave_mechanics dopplers_effect Question 48
Question: A siren placed at a railway platform is emitting sound of frequency 5 kHz. A passenger sitting in a moving train A records a frequency of 5.5 kHz while the train approaches the siren. During his return journey in a different train B he records a frequency of 6.0 kHz while approaching the same siren. The ratio of the velocity of train B to that of train A is
[IIT-JEE (Screening) 2002]
Options:
A) 242/252
B) 2
C) 5/6
D) 11/6
Show Answer
Answer:
Correct Answer: B
Solution:
In both the cases observer is moving towards, the source.
Hence by using $ {n}’=n( \frac{v+v _{0}}{v} ) $ When passenger is sitting in train A, then $ 5.5=5( \frac{v+v _{A}}{v} ) $ ?(i) when passenger is sitting in train B, then $ 6=5( \frac{v+v _{B}}{v} ) $ ?(ii) On solving equation (i) and (ii) we get $ \frac{v _{B}}{v _{A}}=2 $
BETA
