wave_mechanics dopplers_effect Question 53
Question: Two trains are moving towards each other at speeds of 20 m/s and 15 m/s relative to the ground. The first train sounds a whistle of frequency 600 Hz. the frequency of the whistle heard by a passenger in the second train before the train meets is (the speed of sound in air is 340 m/s)
[UPSEAT 2002]
Options:
A) 600 Hz
B) 585 Hz
C) 645 Hz
D) 666 Hz
Show Answer
Answer:
Correct Answer: D
Solution:
The frequency of whistle heard by passenger in the train B, is $ {n}’=n( \frac{v+v _{0}}{v-v _{s}} )=600( \frac{340+15}{340-20} )\approx 666\ Hz $
BETA
