Question

Ice starts forming on the surface of a lake and takes $8$ hours to form a layer of $1$ cm thickness. How much time will it take to increase the thickness of the layer to $2$ cm?

• A. 8 hours
• B. less than 8 hours
• C. between 8 hours and 16 hours
• D. more than 16 hours

Answer 1

Answer: (D)

more than 16 hours

As we know that $Q=\frac{KA\Delta T\times t}{L}$
So we can say $\frac{t_1}{L_1}=\frac{t_2}{L_2}$
where $t$=time duration
$L$=thickness
So, $t_2=\frac{8\times 2}{1}=16hours$
So, it will take 16 hours or more than 16 hours, according to option we have to choose the correct option.