Question

If the radius of a sphere is doubled, it volume becomes ..... times the original volume.

• A. two
• B. four
• C. eight
• D. sixten

Answer 1

Answer: (C)

eight

Let $r$ be the radius of the original sphere.

Then its volume will be $V=\frac{4}{3}\times \pi \times r^3$.

Now if the radius be doubled then the radius of the new sphere will be $2r$.

Then its volume will be $V^{\prime }=\frac{4}{3}\times \pi \times (2r{)}^3=8V$.