Question

Outer surface area of a hollow iron sphere is $1256c{m}^2$. If thickness of iron is $1cm$. Find its capacity.

• A. $3052c{m}^3$​
• B. $1526c{m}^3$​
• C. $6104c{m}^3$​
• D. $9156c{m}^3$​

Answer 1

The correct option is A $3052c{m}^3$​

Surface area of the sphere,
$S=4\pi r^2=1256c{m}^2$
$4\times 3.14\times r^2=1256c{m}^2$
$\Rightarrow r=10cm$

Thickness of the iron = 1 cm
So, inner radius = 9 cm

Volume of air is euqal to the inner volume of sphere.
$V=\frac{4}{3}\pi r^3$
$V=\frac{4}{3}\times 3.14\times 9^3$
$V\approx 3052c{m}^3$​