Question

The given figure shows a toy made of very thin metal sheet. The toy has a hemisphere a cylinder and a cone all of the same radius.

Assertion (A): A minimum area of metal sheet required is: Curved surface area of the conical part + curved surface area of the cylinder part − curved surface area of the hemisphere part

Reason (R): Metal sheet required = Curved surface area of (conical part + cylindercal part + hemispherical part)

Options

• A is true, R is false.

• A is false, R is true.

• Both A and R are true and R is the correct reason for A.

• Both A and R are true and R is the incorrect reason for A.

Answer 1

A is false, R is true.

Explanation:

The toy has the hemisphere, a cylinder and a cone all of the same radius.

Metal sheet required = minimum area of metal sheet required

= curved surface area of conical part + curved surface area of cylinder part + curved surface area of hemisphere part

= curved surface area of (conical part + cylindrical part + hemispherical part)

∴ A is false, R is true.