Question

Curved surface area of solid sphere is $24{cm}^2$. If the sphere is divided into two hemispheres, then the total surface area of one of the hemisphere is

• A. $12{cm}^2$
• B. $8{cm}^2$
• C. $16{cm}^2$
• D. $18{cm}^2$

Answer 1

Answer: (D)

$18{cm}^2$

We have,

Curved surface area $=24c{m}^2$

We know that the curved surface area of the sphere

$=4\pi r^2$

So,

$4\times \frac{22}{7}\times r^2=24$

$r^2=\frac{6\times 7}{22}c{m}^2$

Since, if this sphere is divided into two hemispheres, then total surface area of one hemisphere

$=3\pi r^2$

$=3\times \frac{22}{7}\times \frac{6\times 7}{22}$

$=3\times 6$

$=18c{m}^2$

Hence, this is the answer.