Q. There is formation of layer of snow $x\ cm$ thick on water, when the temperature of air is $- \theta ℃$ (less than freezing point). The thickness of layer increases from $x$ to $y$ in the time $t$, then the value of $t$ is given by
A) $\frac{(x + y)(x - y)\rho L}{2k\theta}$
B) $\frac{(x - y)\rho L}{2k\theta}$
C) $\frac{(x + y)(x - y)\rho L}{k\theta}$
D) $\frac{(x - y)\rho Lk}{2\theta}$
Explanation
(a) Since, $t = \frac{\rho L}{2k\theta}(x_{2}^{2} - x_{1}^{2})$
$\therefore t = \frac{\rho L}{2k\theta}\left( x^{2} - y^{2} \right) = \frac{\rho L(x + y)(x - y)}{2K\theta}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.