Question

an electron enters a magnetic field at right angles to it, as shown in fig 13.14 (pg231 science tb ,class 10) the direction of force acting on the electron will be

(a) to the right (b) to the left (c) out of the page (d) into the page

why is the answer (d)?

Answer 1

When a force conductor carrying current is placed perpendicular to the direction of magnetic field,
the acting on it is given by Fleming's left hand rule. Since the direction of current is the same as that
of the motion of a positive charge, the direction ot force acting on it when moving perpendicular
to the direction of magnetic field is the same as that acting on a current-carrying conductor placed perpendicular to the direction of magnetic field. Obviously, the force acting on an electron is opposite to that. Therefore in this case it is into the page.