A spherical iron ball of 10 | Monotonicity

JEE MAIN 2020

09-01-20 S1

Question

A spherical iron ball of 10 cm radius is coated with a layer of ice of uniform thickness that melts at a rate of $50 \mathrm{~cm}^3 / \mathrm{min}$. When the thickness of ice is 5 cm , then the rate (in $\mathrm{cm} / \mathrm{min}$.) at which of the thickness of ice decreases, is

Select the correct option:

$\frac{1}{36 \pi}$

$\frac{1}{18 \pi}$

$\frac{1}{54 \pi}$

$\frac{1}{6 \pi}$

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution