When source of sound moves towards a stationary observer, the apparent frequency heard by him

Step-by-step solution

For a sound source moving toward a stationary observer, the Doppler effect causes both frequency and wavelength to change. The apparent frequency is given by f' = f ( v v - v_s ) , where v is the speed of sound, f is the source frequency, and v_s is the source speed. Since v_s > 0 , the denominator v - v_s f . The frequency increases. The apparent wavelength becomes ' = v - v_s f . Comparing to the original wavelength = v f , we have ' = - v_s f , which is less than since v_s > 0 . The wavelength decreases. Therefo