Question

If the radius of a cylinder is doubled and the height remains same, the volume will be

Options

• doubled

• halved

• same

•  four times

Answer 1

Let V₁ be the volume of the cylinder with radius r₁ and height h₁, then

 `V_1 = pi r_1^2 h_1`……. (1)

Now, let V₂ be the volume after changing the dimension, then

`r_2 = 2r_1 , h_2 = h_1`

So,

`V_2 = pi r_2^2 h_2 = pi xx (2r_1)^2 xx h_1`

`⇒ V_2 = 4 xx pi r_1^2 h_1 = 4V_1`