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

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 train A is [2002]

Smart Achievers · Accepted Answer

(2)

$Using the formula f' = f (\frac{v_{A} + v}{v})$

$\frac{v_{A} + v}{v} = \frac{5.5}{5}$ $and$ $\frac{V_{B} + V}{V} = \frac{6}{5}$

$∴$ $\frac{v_{B}}{v_{A}} = 2$

Solution

1 $\frac{242}{252}$

2 $2$

3 $\frac{5}{6}$

4 $\frac{11}{6}$

Ans.
(2)

$Using the formula f' = f (\frac{v_{A} + v}{v})$

$\frac{v_{A} + v}{v} = \frac{5.5}{5}$ $and$ $\frac{V_{B} + V}{V} = \frac{6}{5}$

$∴$ $\frac{v_{B}}{v_{A}} = 2$

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Solution

1 242252

2 2

3 56

4 116