MCQ
At what speed should a source of sound move so that stationary observer finds the apparent frequency equal to half of the original frequency
- A$\frac{v}{2}$
- B$2v$
- C$\frac{v}{4}$
- ✓$v$
✓
Answer
Correct option: D.
$v$
d
(d) Frequency is decreasing (becomes half), it means source is going away from the observes. In this case frequency observed by the observer is
(d) Frequency is decreasing (becomes half), it means source is going away from the observes. In this case frequency observed by the observer is
$n' = n\left( {\frac{v}{{v + {v_s}}}} \right)$ ==> $\frac{n}{2} = n\,\left( {\frac{v}{{v + {v_S}}}} \right)$ ==>${v_S} = v$
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