A long straight horizontal cable carries a current of 2.5 A in the direction `10^@` north of east . The magnetic meridian of the place happens to be `10^@` west of the geographic meridian The earth's magnetic field at the location is 0.33 G , ad the angle of dip is zero. Locate the line of neutral points (ignore the thickness of the cable ) (At neutral points , magnetic field due to a current - carrying cable is equal and opposite to the horizontal component of earth's magnetic field ).

Explanation

Since the current is from west to east, magnetic lines of field are in the same direction below but in opposite direction above . Al neutral point , field of conductor = field of earth
i.e., `(mu_0I)/(2pia)=B " or " a = (mu_0I)/(2piB)`