Question

A sound source of frequency 170 Hz is placed near a wall. A man walking from the source normally towards the wall finds that there is a periodic rise and fall of sound intensity. If speed of sound in air is 340 m/s, the distance in meters separating the two adjacent position of minimum intensity is:

• A. $\frac{1}{2}$
• B. $1$
• C. $\frac{3}{2}$
• D. $2$

Answer 1

The correct option is B $1$

According to the question,

$v=n\lambda$

$=\frac{v}{n}$

$=\frac{340}{170}$

$\lambda =2$

The distance separating the position of minimum intensity

$=\frac{\lambda }{2}$

$=\frac{2}{2}$

$=1m$