It takes 2 liters to paint the surface of a solid sphere. If this solid sphere is sliced into 4 identical pieces, how many liters will be required to paint all the surfaces of these 4 pieces.
Explanation:
Total outer surface area of a sphere of radius r = 4πr2
When the sphere is cut into 4 identical pieces, each piece will expose πr2/2 + πr2/2 = πr2 area more.
∴ Now, 4πr2 additional area needs to be painted which will require 2 more liters of paint.
∴ 4 litres of paint will be needed.
Hence, option (d).
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