A train blowing its whistle moves with a constant velocity `v` away from an observer on the ground. The ratio of the natural frequency of the whistle to that measured by the observer is found to be `1.2`. If the train is not rest and the observer moves away from it at the same velocity, this ratio would be given byA. `0.51`B. `1.25`C. `1.52`D. `2.05`

A train blowing its whistle moves with a constant velocity `v` away fr

1.	A train blowing its whistle moves with a constant velocity `v` away from an observer on the ground. The ratio of the natural frequency of the whistle to that measured by the observer is found to be `1.2`. If the train is not rest and the observer moves away from it at the same velocity, this ratio would be given byA. `0.51`B. `1.25`C. `1.52`D. `2.05`
Answer» Correct Answer - B `f_(1) = f_(0) (v_("sound"))/(v_("sound") + v_("train")) = (1)/(1.2)f_(0) rArr 1.2 v_("sound") = v_("sound") + v rArr v = (v_("sound"))/(5)` `f_(2) = f_(0) (v_("sound") - v_("man"))/(v_("sound")) = 0.8 rArr (f_(0))/(f_(2)) = 1.25`

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