When source of sound and observer both are moving towards each other, the observer will hear

Step-by-step solution

When a source and observer move toward each other, the relative velocity increases, altering both frequency and wavelength through the Doppler effect. The apparent frequency is given by f' = f₀ ( v + v_o v - v_s ) , where v is the speed of sound, v_o is the observer's speed, and v_s is the source's speed. The positive terms v_o and v_s ensure v + v_o v - v_s > 1 , so f' > f₀ . Since v = f remains constant, the wavelength must decrease as frequency increases: ' = v f' The observer thus hears a high frequency and low