A train moves towards a stationary observer with speed 34 m s - 1 . The train sounds a whistle and its frequency registered by the observer is f 1 . If the train's speed is reduced to 17 m s - 1 , the frequency registered is f 2 . If the sp

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A train moves towards a stationary observer with speed 34 m s - 1 . The train sounds a whistle and its frequency registered by the observer is f 1 . If the train's speed is reduced to 17 m s - 1 , the frequency registered is f 2 . If the speed of sound is 340 m s - 1 , then the ratio f 1 f 2

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Correct answer: D. 19 18

Here, v s 1 = 34 m s - 1 , v = 340 m s - 1 f 1 = v × n v - v s 1 = 340 × n 340 - 34 = 340 306 n f 2 = v × n v - v s 2 = 340 × n ( 340 - 17 ) = 340 n 323 f 1 f 2 = 323 306 = 19 18

A train moves towards a stationary observer with speed 34 m s - 1 . The train sounds a whistle and its frequency registered by the observer is f 1 . If the train's speed is reduced to 17 m s - 1 , the frequency registered is f 2 . If the speed of sound is 340 m s - 1 , then the ratio f 1 f 2

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