Question

In a cylinder, if radius is halved and height is doubled, the volume will be (a) same (b) doubled

(c) halved (d) four times

Answer 1

The correct option is

Let r be radius and h be height, then

Volume = $\pi r^2$ h

If radius is halved and height is doubled

Then volume =$\pi {\left(\frac{1}{2}r\right)}^2\times \left(2h\right)$

=$\pi \times \frac{1}{4}{r}^2\times 2h=\frac{1}{2}\pi r^2$ h

$\therefore$ It is halved

Hence the correct answer is (c) halved