State the common properties between Doppler effect of sound and light.

i. The recorded frequency is different than the emitted frequency in case of relative motion between listener (or observer) and source (of sound or light waves).

ii. In case of relative approach, recorded frequency > emitted frequency.

iii. In case of relative recede, recorded frequency < emitted frequency.

iv. For values of listener velocity (v_L) or source velocity (v_s) much smaller then wave speed (speed of sound or light).

n = n₀ \((1\pm \frac{v_r}{v})\)

Where, vr = relative velocity

n = actual frequency of the source

n₀ = apparent frequency of the source

v = velocity of sound in air.

(upper sign is used during relative approach and lower sign is during relative recede.)

v. If velocities of source and observer (listener) are along different lines, their respective components along the line joining them should be chosen for longitudinal Doppler effect and the same mathematical treatment is applicable.