The time of reverberation of a room A is one second. What will be...

Sabine formula for reverberation time is $T=\frac{0.16 \mathrm{~V}}{\Sigma a S}$ where $V$ is volume of hall in $\mathrm{m}^3$. $\Sigma a S=a_1 S_1+a_2 S_2+\ldots$ = total absorption of the hall (room) Here, $S_1, S_2, S_3 \ldots \ldots$ are surface areas of the absorbers and $a_1, a_2, a_3 \ldots$. . are their respective absorption coefficients. $\therefore \quad \frac{T^{\prime}}{T}=\frac{V^{\prime}}{S^{\prime}} \times \frac{S}{V}=\frac{(2)^3}{(2)^2}=\frac{8}{4}=2$ Hence, $\quad T^{\prime}=2 T=2 \times 1=2 \mathrm{~s}$