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A siren placed at a railway platfrom is ...

A siren placed at a railway platfrom is emitted sound of frequency `5 kH_(Z)`, A passenger sitting in retun journey in a different train `B` he records a frequency of `6.0 kH_(Z)` while approaching the same siren. The ratio of the velocity of train `B` to that of train `A` is

A

`(242)/(252)`

B

2

C

`(5)/(6)`

D

`(11)/(6)`

Text Solution

Verified by Experts

The correct Answer is:
D
`f_(approach)_(A)=5.5kHz=((v+v_A)/(v))5` ..(i)
`f_(approach)_(B)=6kHz=((v+v_B)/(v))5` ..(ii)
Where `v` is the velocity of sound. Now,
`5.5=(1+(v_A)/(v))5`
`implies(v_A)/(v)=0.1` .(iii)
similarly, `6=(1+(v_B)/(v))5`
`implies(v_B)/(v)=0.2` .(iv)
`implies(v_B)/(v_A)=2`
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CENGAGE PHYSICS ENGLISH-SOUND WAVES AND DOPPLER EFFECT-Single Correct
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