Waves - Result Question 62

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64. Two waves of lengths $50 cm$ and $51 cm$ produce 12 beats per sec. The velocity of sound is [1999]

======= ####64. Two waves of lengths $50 cm$ and $51 cm$ produce 12 beats per sec. The velocity of sound is [1999]

3e0f7ab6f6a50373c3f2dbda6ca2533482a77bed:content/english/neet-pyq-chapterwise/physics/waves/waves—result-question-62.md (a) $306 m / s$

(b) $331 m / s$

(c) $340 m / s$

(d) $360 m / s$

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Answer:

Correct Answer: 64. (a)

Solution:

  1. (a) Given : Wavelength of first wave $(\lambda_1)$

$=50 cm=0.5 m$

Wavelength of second wave $(\lambda_2)$

$=51 cm=0.51 m$

frequency of beats per $\sec (n)=12$.

We know that the frequency of beats,

$n=12=\frac{v}{\lambda_1}-\frac{v}{\lambda_2}$

$\Rightarrow 12=v[\frac{1}{0.5}-\frac{1}{0.51}]$

$=v[2-1.9608]=v \times 0.0392$

or, $v=\frac{12}{0.0392}=306 m / s$

[where, $v=$ velocity of sound]