JEE · NEET Previous Year Question
A boy is walking away from a wall towards an observer at a speed of 1 meter/sec and blows a whistle whose frequency is 680 Hz. The number of beats heard by the observer per second is (Velocity of sound in air = 340 meters/sec
Topic: NEET PYQ
Answer: D. Full step-by-step solution below.
- AZero
- B2
- C8
- D4
Correct answer: D
Solution
(d) Observer hears two frequencies(i) which is coming from the source directly
(ii) which is coming from the reflection image of source
so, and
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