Answer is C .
The reason is as follows:
Nuclear forces don’t obey inverse square law.
Neither the strong nuclear force nor the weak nuclear force follow the inverse square law.
The weak nuclear force is a Yukawa-type force. Such a force is characterized by a potential in the form ∝−/
∝
e
−
m
r
/
r
. At short range ( ≪1
m
r
≪
1
) the exponential term is just 1
1
, so the potential becomes an inverse-
r
potential with an inverse square force law associated with it. So at very short (subatomic) ranges, the weak nuclear force is actually very similar to the electromagnetic force. But as soon as >1
m
r
>
1
, the force rapidly vanishes and becomes undetectable.
The strong nuclear force does not decrease with distance. Which means that as you “stretch” the bond between two quarks, for instance, more and more energy needs to be invested; until there is enough energy to create a new quark-antiquark pair, at which point the bond breaks. This limits the range of the strong nuclear force to subatomic scales, too.
