If a source emitting waves of frequency 'F' moves towards an observer with a velocity V 3 and the observer moves away from the source with a velocity V 4 , the apparent frequency as heard by the observer will be ( V = velocity of sound)

Step-by-step solution

Apparent frequency for Doppler effect in sound The apparent frequency F' follows the formula F' = F ( V v_o V v_s ) , where F is the source frequency, V is the speed of sound, v_o is the observer velocity, and v_s is the source velocity. Sign conventions determine the operator: observer moving away uses V - v_o in numerator, source moving toward uses V - v_s in denominator. Given v_s = V 3 (toward observer) and v_o = V 4 (away from source), we substitute: F' = F ( V - V 4 V - V 3 ) = F ( 3V 4 2V 3 ) Simplifying the