JEE MAIN - Physics (2010 - No. 14)
Two long parallel wires are at a distance $$2d$$ apart. They carry steady equal currents flowing out of the plane of the paper as shown. The variation of the magnetic field $$B$$ along the line $$XX'$$ is given by
Giải thích
The magnetic field varies inversely with the distance for a long conductor. That is, $$B \propto {1 \over d}.$$ According to the magnitude and direction shown graph $$(1)$$ is the correct one.