The area of the curved surface of a cone of radius 2r and slant height `l/2` is a) `pirl` b)`2pirl` c)`1/2 pir l` d)`pi(r+l)r`

Explanation

Radius of a cone = `2r`

Slant height = `l`

Area of cone = `pixxrxxl`

Area of cone = `pixx2rxl`=`2(pi)rl`

Hence, option(b) is correct.