Question

A metal sphere with radius of $10cm$ is to be covered with a $0.02cm$ coating of silver approximately silver required is (in $c{m}^3$)

• A. $2\pi$
• B. $10\pi$
• C. $6\pi$
• D. $8\pi$

Answer 1

The correct option is D $8\pi$

$V=\frac{4}{3}\pi r^3\Rightarrow dV=4\pi r^{2}h$
when $r=10$ and $h=0.02$
We have $dV=4\pi {\left(10\right)}^2\left(0.02\right)=8\pi$