There is formation of layer of snow x cm thick on water, when the temperature of air is `-theta^(@)C` (less than freezing point). The thickness of layer increased from x to in the time t, then the value of t is given by :

Options

A. `((x-y)(rhoLK))/(2theta)`
B. `((x+y)(x-y)rhoL)/(ktheta)`
C. `((x+y)(y-x)rhoL)/(2ktheta)`
D. `((x-y)rhoL)/(2ktheta)`

Answer

C

Explanation

We know that time taken to increase the thickness of snow from x to y is
`t(rhoL)/(2ktheta)(y^(2)-x^(2))=(rhoL(y-x)(y+x))/(2ktheta)`
Correct choice is (c).