Question

Who will hear the voice of a singer first: a person in the balcony 50.0 m away from the stage, or a person 1500 km away at home whose ear is next to the radio listening to the live broadcast? Roughly how much sooner? Ignore the time for the sound to travel to the microphone. [Speed of sound : 343 m/s.]

A.Person at the radio hears the voice 1 s sooner.

B.Person in the balcony hears the voice 8.7 s sooner.

C.Person in the balcony hears the voice 0.14 s sooner.

D. Person at the radio hears the voice 0.14 s sooner.

E.Person in the balcony hears the voice 1 s sooner.

Answer 1

The Person whose ear is next to radio will get it first because the person at the balcony will heart at the rate of speed of sound i.e. 343m/s while the one near the radio will recieve the frequency at speed of light i.e.3 x 10⁸ m/s

time taken to reach home = 1.5 x 10⁶ / 3 x 10⁸   (using speed = distance / time)

= 0.005 sec

time taken by sound to reach balcony = 50 / 343 =0.1458 sec ( which is greater than above)

the Person by the radio will get 0.1458 - 0.005 =0.14 sec sooner than at balcony ....