Waves - Result Question 3
3. Sound waves travel at $350 m / s$ through a warm air and at $3500 m / s$ through brass. The wavelength of a $700 Hz$ acoustic wave as it enters brass from warm air
[2011] (a) decreases by a factor 10
(b) increases by a factor 20
(c) increases by a factor 10
(d) decreases by a factor 20
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Answer:
Correct Answer: 3. (c)
Solution:
- (c) We have, $v=n \lambda$
$\Rightarrow v \propto \lambda$ (as $n$ remains constant)
Thus, as $v$ increases 10 times, $\lambda$ also increases 10 times.
