Question

If two solid hemispheres of same base radius r are joined together along their bases, then curved surface area of this new solid is

• A. $4\pi r^2$
• B. $6\pi r^2$
• C. $3\pi r^2$
• D. $8\pi r^2$

Answer 1

The correct option is A $4\pi r^2$

We know that,

Curved surface area of a hemisphere $=2\pi r^2$

So, when two solids hemispheres of same base radius are joined together along their bases, then

Curved surface area of newly formed solid sphere$=2\times 2\pi r^2=4\pi r^2$

Hence, A is the correct option.