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Sahay Sir > Question Answers > NCERT Exemplar Class 12 > Physics > Chapter 10 - Wave Optics > A train standing at the outer signal of a railway station blows a whistle of frequency 400 Hz in still air. (i) What is the frequency of the whistle for a platform observer when the train (a) approaches the platform with a speed of 10 m/s (b) recedes from the platform with a speed of 10 m/s ? (ii) what is the speed of sound in each case? The speed of sound in still air can be taken as 340 m/s

A train standing at the outer signal of a railway station blows a whistle of frequency 400 Hz in still air. (i) What is the frequency of the whistle for a platform observer when the train (a) approaches the platform with a speed of 10 m/s (b) recedes from the platform with a speed of 10 m/s ? (ii) what is the speed of sound in each case? The speed of sound in still air can be taken as 340 m/s

A string of mass 2.50 kg is under a tension of 200 N. The length of the stretched string is 20.0 m. If the transverse jerk is struck at one end of the string how long does he disturbance take to reach the other end ?