Question : If the radius of a sphere is doubled, then its surface area will be increased by:

Option 1: 100%

Option 2: 200%

Option 3: 300%

Option 4: 400%

Question : When the radius of a sphere is increased by 5 cm, its surface area increases by 704 cm². The diameter of the original sphere is _________. (Take $\pi=22 / 7$ )

Option 1: 8.2 cm

Option 2: 6.8 cm

Option 3: 5.2 cm

Option 4: 6.2 cm

Question : Which of the following statements is not correct?

Option 1: For a given radius and height, a right circular cone has a lesser volume than a right circular cylinder.

Option 2: If the side of a cube is increased by 10%, the volume will increase by 33.1%.

Option 3: If the radius of a sphere is increased by 20%, the surface area will increase by 40%.

Option 4: Cutting a sphere into 2 parts does not change the total volume.

Question : The radius of a hemisphere is twice that of a sphere. What is the ratio of the total surface area of the hemisphere and sphere?

Option 1: 3 : 1

Option 2: 12 : 1

Option 3: 4 : 1

Option 4: 6 : 1

Question : If the radius of a hemispherical balloon increases from 4 cm to 7 cm as air is pumped into it, find the ratio of the surface area of the new balloon to its original.

Option 1: 16 : 21

Option 2: 49 : 16

Option 3: 20 : 49

Option 4: 21 : 12