Q: The radius of metal sphere at room temperature T is R and the coefficient of linear expansion of the metal is α . The sphere heated a little by a temperature ΔT so that its new temperature is T + ΔT. the increase in the volume of the sphere is approximately.
(a) 2 π R α ΔT
(b) 2 π R2 α ΔT
(c) 4π R3α ΔT/3
(d) 4π R3α ΔT
Ans: (d)