In the Standard Model the weak and the electromagnetic interactions are combined into a unified electroweak theory.

Weak charges are closely related to electromagnetic charges and are not actually small compared to them in an important sense. Notice from the relative strengths table that at very short distances (10 to the -18 meters) the strength of the weak interaction is comparable to the electromagnetic. But, at 30 times that distance (still much less than the average separation of quarks in a proton or neutron), the strength of the weak interaction is much smaller than the electromagnetic interaction.

The weak and electromagnetic interaction appear at first sight to have very different strengths, but their strengths are in fact approximately equal. The difference between them is due to the huge difference in mass between the W and Z, which are heavy, and the photon which is massless.

This is because the interaction potential falls off as:

Where m is mass and r is distance.

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Question: When are the electromagnetic and the weak interactions comparable in strength?