Two parallel beams of protons and electrons, carrying equal currents are fixed at a separation d. The protons and electrons move in opposite directions. There is a point P on the straight perpendicular line joining the two beams at a distance x from one beam. The magnetic field at this point is B. If B is plotted against x, it can be represented by the curve.

Options

A.
B.
C.
D.

Answer

C

Explanation

The magnetic field at points to be the right of the proton beam acts perpendicular to the paper inwards `(')`. The magnetic field at points to the left of the electron beam acts perpendicular to the paper outwards `(X)`.
Magnetic field at mid point `M` is zero.

Magnetic field at the points closer to proton beam acts perpendicular to the paper inwards `(i.e.,('))` and at the points closer to electron beam it acts outwards `i.e.(X)`. In the given options graph `(c )` satisfies all the conditions