A small neutral metal sphere is placed at a large distance from a point charge. By what factor would the Coulomb force between the charge and the sphere change if the distance between them is doubled?

We received many solutions from all over the world for our December Challenge, 2b or not 2b? We are pleased to recognize the following contributors:

Guidelines for contributors

Many thanks to all contributors and we hope to hear from many more of you in the future!

Note: as always, we would very much appreciate reader-contributed original Challenges.

Boris Korsunsky, Column Editor

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