There is a source of sound (a tuning fork) moving towards a reflecting wall will a speed of 30 m s - 1 . The velocity of the sound in air is 330 m s - 1 and the frequency of the tuning fork is 600 Hz . The observer is between the source and the wall and is moving with some velocity V 1 towards the wall. The beat frequency heard by the observer is 4 Hz . If the tuning fork is waxed, the frequency beats heard by the ob

Step-by-step solution

Apparent frequency of source = n 0 c - v 1 c - v 2 = n ′ Apparent frequency of reflected sound = n 0 c + v 1 C - V = n ′ ′ Beat frequency = n ′ ′ - n ′ = 2 n 0 V 1 C - V 2 = 2 × 600 × V 1 330 - 30 = 4  Hz ∴     V 1 =   1   m   s - 1 When the tuning fork is waxed let its frequency become k Beat frequency = 2 k v 1 C - V 2 = 2 × k × 1 330 × 30   = 3  H z ∴       k = 450  H z = new frequ