According to Coulomb's law, the force between the two magnets is expressed as
F = μom1m2/4πr^2
where
F is the force
m1 and m2 are the pole strength of the magnets
r is the distance between the magnets
μo is the permeability constant
If every thing remains tha same and the distance is doubled, it means that r = 2r
Thus,
F = μom1m2/4π * 2^2 = μom1m2/4π * 1/4
Thus, the correct option is
D) one-fourth as much
