If a spherical metal bob of radius 3cm is fully immersed in a cylinder containing water and the water level rises by 1cm, what is the radius of the cylinder?
- 12cm
- 1cm
- 3cm
-
6cm
The correct answer is: D
Explanation
If the bob is fully immersed in the water, then the volume of water displaced will be equal to the volume of the bob = 4/3πr3, where r is the radius of the bob.This volume of water in the cylinder = πr2l, where r = radius of the cylinder, and l = level of water rose in the cylinder.
Therefore, π x r2 x l = 4/3 x π x 33
Then r2 = 36
r = √36
r = 6cm
There is an explanation video available .