Point P lies on the axis of a short magnetic dipole at a distance of 0.4 m from centre,point Q lies at a distance of 0.25 m from centre of the magnet and on the line inclined at `30^(@)` with the axis of the magnet.The ration of magnetic potentials at P and Q is

Options

A. 1.45
B. 0.5
C. 2.45
D. 0.45

Answer

D

Explanation

`V_(P)/(V_(Q))=(r_(Q)^(2))/(r_(p)^(2)costheta)=(625xx10^(-4))/(16xx10^(-2)xxcos30)=0.45`