A vertical straight conductor carries a current vertically upwards. A point `P` lies to the east of it at a small distance and another point `Q` lies to the west at the same distance. The magnetic field at `P` is

Options

A. Less than at Q
B. Greater or less that at Q depending upon the strength of the currrent
C. Greater than at Q
D. The same as at Q

Answer

D

Explanation

`B=(mu_0)/(4pi)(2i)/(r)`, as P and Q are equidistant from the wire, ` r_1=r_2=r` Magnitude of the field at P=Magnetude of the field at Q