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

Explanation

let radius `=r`

and height `=h`

so volume `v=pixx(r^2)h`

in new case radius `R=r/2`

height `H=2h`
so new volume `V=pixx(r/2)^2(2h)`

`=(1/2)xx[pixx(r^2)h]`

`=(1/2)v`
so ans is (d) halved