Question

If the height of a cylinder is doubled and radius remains the same, then 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 = r_1 , h_2 = 2h_1`

So,

`V_2 = pir_2^2 h_2 = pi xx r_1^2 xx 2h_1`

`⇒ V_2 = 2 xx pi r_1^2 h_1 = 2V_1`