Notes

Different situation in Apparent Frequency…

Different situation in Apparent Frequency –
(i) If source is moving towards listener but listener is at rest, then v_s is positive and v_o = 0
∴ f’ = v/v – v_s × f, i.e. f’ > f
(ii) If source is moving away from listener but listener is at rest, then v_s is negative and v_o = 0.
∴ f’ = [v/v – (-v_s) × f
= (v/v + v_s) × f i.e. f’ < f
(iii) If source is at rest and listener is moving away from source, then v_s = 0 and v_o is position.
∴ f’ = (v – v_o/v) × f i.e. f’ < f