Let us assume that an electron can be considered as a ball of radius o, on the surface of which an electric charge e is uniformly distributed. It can be shown that outside this ball and on its surface the field is the same as that of a point charge; the field inside the ball is zero. Based on these considerations, find the electron field energy. Assuming that it is equal to the rest energy of the electron, estimate the radius of this ball. Compare with Problem 14.23.

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