Question

It takes 2.0 seconds for a sound wave to travel between two fixed points when the day temperature is ${10}^{\circ }$C. If the temperature rise to ${30}^{\circ }$C. the sound wave travels between the same fixed parts in

• A. 1.9 sec
• B. 2.0 sec
• C. 2.1 sec
• D. 2.2 sec

Answer 1

The correct option is A 1.9 sec

Suppose the distance between two fixed points is d then
$t=\frac{d}{v}$ also $v\propto \sqrt{T}\Rightarrow \frac{t_1}{t_2}=\frac{v_2}{v_1}=\sqrt{\frac{T_2}{T_1}}$
$\Rightarrow \frac{2}{t_2}=\sqrt{\frac{303}{283}}\Rightarrow t_2=1.9$ sec.