Question

The time period of a sound wave travelling in a medium is $T$. At a given instant $t=0$, a particular region in a medium has minimum density. The density of this region will be minimum again at

• A. $t=T$
• B. $t=\frac{T}{2}$
• C. $t=\frac{T}{3}$
• D. $t=\frac{T}{4}$

Answer 1

The correct option is A $t=T$

Its a low or minimum density region, so it is a rarefaction.
From $t$ $=$ $0$, next rarefaction will be produced at $t=\frac{T}{2}+\frac{T}{2}=T$