Question

A train has just completed U-curve in a track which is a semicircle. The engine is at the forward end of the semi-circular part of the track while the last carriage is at the rear end of the semi circular track. The driver blows a whistle of frequency 200 Hz. Velocity of sound is 340 m/sec Then the apparent frequency as observed by a passenger in the middle of the train, when the speed of the train is 30 m/sec is 

(a) 181 Hz 

(b) 200 Hz 

(c) 188 Hz 

(d) 210 Hz

Answer 1

Correct option: (b) 200 Hz

Explanation: 

As passenger is a part of moving train, there is no relative motion between source and listener. Therefore, n' = n = 200 Hz