Question

A right circular cylindrical tunnel of diameter 2 m and length 40 m is to be constructed from a sheet of iron. The area of the iron sheet required in m², is

Options

• 40 \[\pi\]

   

• 80 \[\pi\]

   

• 160 \[\pi\]

   

• 200 \[\pi\]

   

Answer 1

Let r be the radius of the cylinder and h be its height.

It is given that:

`2r = 2 ⇒ r = 1 m`

And,

 h = 40 m

Therefore, total surface area S of the sheet required is:

`S = 2 pirh`

`⇒ S = 2pi xx 1xx40`

`⇒ S = 80pi  m^2`