Question

How do you descrie the elecrical force between protons and neutrons?

Answer 1

According to Coulomb's law, the electrostatic force F between two charges(q1,q2) present at a certain distance apart say r is given by

F = kq1q2/r2 .........eqn 1

where k is the constant of proportionality.

Now, if we observe eqn 1,f would be -ve if q1q2<0 i.e product of magnitude of two charges is less that zero.

q1q2<0 signifies that either of one charges is negative, i.e we have charges of oppposite polarities and hence the force is attractive in nature.

However, q1q2>0 implies that either both the charges are positive or negative, hence the Force would be positive i.e repulsive in nature.

It must be noted that Coulomb force acts only between the charged particles.

Hence if we have an electron proton system,say it charge be q1 and q2, then

q1q2<0 hence the force would be attractive in nature

If we have electron electron, or proton proton system, then

q1q2>0, hence the force would be repulsive in nature

However, if we take into consideration the proton neutron system, we know that

qproton = +ve

qneutron = 0

Hence, if we use these values in eqn 1,

F = k(+ve value)(0)/r2 = 0

i.e Coulomb's force or Electrical force acting between a proton and neutron is zero.

This suggests that in the nucleus, the proton and neutron are held together by a force other than Electrical force.