A violin player riding on a slow train plays a 440 Hz note. Another violin player standing near the track plays the same flute, When the two are close by and the train approaches the person on the ground, he hears 4.0 beats per second. The speed of sound in air = 340 m/s. (a; Calculate the speed of the train. (b) What beat frequency is heard by the player in the train?

Question

Philoid · Accepted Answer

(a) The person standing hears 4 beats per second. Hence the apparent frequency will be

Now, according to Doppler’s effect,

(b)

Now, for the person in the train the apparent frequency will be,

Hence, he will hear a little less than 4 beats per second.