(a) List four factors on which the magnitude of magnetic force acting on a moving charge in a magnetic field depend.
(b)How will a fine beam of electrons streaming in west to east direction be affected by a magnetic field directed vertically upwards ? Explain with the help of a diagram mentioning the rule applied.

Explanation

(a) Magnitude of magnetic force acting on a moving charge in a magnetic field depends on (i) the magnitude of charge, (ii) speed of moving charge, (ii) strength of magnetic field, and (iv) the angle between the direction of motion of charge and the direction of magnetic field.
(b)The electron streaming from west to east is equivlaent to a current from east to west . The magnetic field B is vertically upwards and shown by cross mark(x). Hence , in accordance with Fleming .s left hand rule , the electron will experience force in north direction and deflected in that direction .