Question

Two waves of lengths 50 cm and 51 cm produce 12 beats/sec. The velocity of sound is:

• A. 360m/s
• B. 340m/s
• C. 331m/s
• D. 306m/s

Answer 1

The correct option is D 306m/s

Beats $={\delta }_1-{\delta }_2$
$\delta =\frac{v}{\lambda }$
So, ${\delta }_1=\frac{v}{{\lambda }_1}and{\delta }_2=\frac{v}{{\lambda }_2}$

$\frac{v}{{\lambda }_1}-\frac{v}{{\lambda }_2}=beat$

$v(\frac{1}{50}-\frac{1}{51})=12$

$v=\frac{12\times 50\times 51}{51-50}=30600cm/s$$=306m/s$