A hollow hemisphere has uniform thickness. Its inner radius is r, and outer radius is R. If R = 2r, find the ratio of outer to inner curved surface areas.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 4:1.
Outer curved surface area = 2πR2 = 2π(2r)2 = 8πr2
Inner curved surface area = 2πr2
Ratio = (8πr2) : (2πr2) = 4 : 1