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Question 3:
The radius of a spherical balloon increases from 7 cm to 14 cm as air is being pumped
into it. Find the ratio of surface areas of the balloon in the two cases.
(a) 4:1 (b) 1:4 (c) 1:1 (d) 4:4

Question 4:
2
What is the radius of a sphere whose surface area is 154 cm ?
(a) 3.5 cm (b) 3.3 cm (c) 5.3 cm (d) 5.5 cm

Question 5:
The diameter of the moon is approximately one- fourth of the diameter of the earth. Find
the ratio of their surface areas.
(a) 1:16 (b) 16:1 (c) 1:4 (d) none of these

Question 6:
A right circular cylinder just encloses a sphere of radius r. Then what is the ratio of
surface area of the sphere to curved surface area of the cylinder ?
(a) 1:1 (b) 4:1 (c) 1:4 (d) none of these

Question 7:
A sphere of radius r has the same volume as that of a cone with a circular base of
radius r. Find the height of the cone.
(a) 2 r (b) 4 r (c) 3 r (d) none of these

Question 8:
What is the surface area of a sphere of diameter 3.5 m ?
(a) 38.5 m (b) 35.8 m (c) 53.8 m (d) none of these
2
2
2
Question 9:
If the radii of a sphere and base of a cylinder are same, then find the ratio of the curved
surface area of sphere to curved surface area of the cylinder if height of the cylinder is 4
times of its radius.
(a) 2:1 (b) 1:2 (c) 1:4 (d) 4:1

Question 10:
If the surface area of a sphere is 5544 cm , then its diameter is
2
(a) 42 cm (b) 24 cm (c) 22 cm (d) 44 cm

Answers
1. (a) 2. (c) 3. (b) 4. (a) 5. (a)

6. (a) 7. (b) 8. (a) 9. (b) 10.(b)