Question
A hemispherical depression is cut out from one face of a cubical wooden block such that the diameter l of the hemisphere is equal to the edge of the cube. Determine the surface area of the remaining solid.
Solution
It is given that,
Edge of the cube = l
Then, Surface area = 6 (edge)2 = 6l2
Now, the greatest diameter of hemisphere
= length of an edge of the cube
= l
So, curved surface area of the hemisphere
And, Area of base of the hemisphere
Required surface area
= Surface area of the cubical wooden block – area of the base of the hemisphere + curved surface area of the hemisphere