Question

A sound wave of frequency $1360Hz$ falls normally on a perfectly reflecting wall. The shortest distance from the wall at which the air particles have maximum amplitude of vibration is ($v=340m/s$)

• A. $25cm$
• B. $6.25cm$
• C. $62.5cm$
• D. $2.5cm$

Answer 1

Answer: (B)

$6.25cm$

$v=f\lambda$
$\lambda =\frac{340}{1360}=\frac{1}{4}=0.25m$
$=25cm$
As the end is a node, shortest distance at which antinode is formed is $\frac{\lambda }{4}=6.25cm$