Question

The radius of a hemisphere having the total surface area of 1848 cm${}^2$ is 7 cm.

• A. True
• B. False

Answer 1

The correct option is B

False

Let the radius of the sphere be $r$ cm.
$\therefore$ Total surface area = Curved surface area + Area of the base

$=2\pi r^2+\pi r^2=3\pi r^2$

Given, total surface area $=1848c{m}^2$

$\therefore 3\pi r^2=1848$

$\Rightarrow 3\times \frac{22}{7}\times r^2=1848$

$\Rightarrow r^2=1848\times \frac{1}{3}\times \frac{7}{22}$

$\Rightarrow r^2=196$
$\Rightarrow r=14cm$
Thus, above statement is false.