The given figure shows a solid cylinder and a solid cone on it according to the given measurement, the total surface area of the solid in terms of π and r is :

1. 4πr²

2. 5πr²

3. 6πr²

4. 7πr²

A solid metal cuboid with dimensions 11 cm, 18 cm and 8 cm is melted and identical solid spheres, each of radius 1 cm, are formed. The number of spheres formed is :

1. 378

2. 1134

3. 1512

4. none of these

A cone and a sphere have equal volumes. If height of the cone = radius of the sphere = 10 cm, the radius of the cone is :

1. 40 cm

2. 10 cm

3. 30 cm

4. 20 cm

By applying force on an uniform metallic wire, the wire is extended four times along its length with same width all around. Then :

(i) The volume of metal in both the cases is same.

(ii) The surface area of solid wires in both the cases is same.

Which of the above statements is/are true?

1. only (i)

2. only (ii)

3. both (i) and (ii)

4. neither (i) nor (ii)