Question

If four times the sum of the areas of two circular faces of a cylinder of height 8 cm is equal to twice the curve surface area, then diameter of the cylinder is

(a) 4 cm

(b) 8 cm

(c) 2 cm

(d) 6 cm

Answer 1

Let r be the radius of cylinder.

Area of circular base of cylinder

The height of cylinder h = 8 cm

The C.S.A. of cylinder

Clearly,

The diameter of cylinder

Hence, the correct answer is choice (b).