Source has frequency f. Source and observer both have same speed. For the apparent frequency observed by…
Source has frequency f. Source and observer both have same speed. For the apparent frequency observed by observer, match the following columns and mark the correct option from the codes given below.
| Column I | Column II |
| --- | --- |
| (A) Observer is approaching the source but source is receding from the observer | (p) more than f |
| (B) Observer and source both are approaching towards each other | (q) less than f |
| (C) Observer and source both are receding from each other | (r) equal to f |
| (D) Source is approaching but observer is receding | (s) None |
(a) p q r s
(b) r p q r
(c) r q p s
(d) r p s q
Solution
Using Doppler formula cases:
A: $f' = f\left(\dfrac{v+v_o}{v+v_s}\right)=f$ (gives match r),
B: $f' = f\left(\dfrac{v+v_o}{v-v_s}\right)>f$ (match p),
C: $f' = f\left(\dfrac{v-v_o}{v+v_s}\right)