State the factors on which the force acting on a charge moving in a magneticfield depends. Write the expression for this force. When is this force maximum andminimum?

The force acting on a charge moving in a magnetic field depends on the magnitude of charge(q), its velocity(v), the magnitude of the magnetic field(B), and the angle between the velocity and field(theta).

F=q(vXB) [cross product of v and B]

=qvBsin(theta)

this force will be maximum (=qvB) when sin(theta) is 1, ie when the angle between the velocity and the magnetic field is 90^o(they are perpendicular)

The force will be minimum (=0) when sin(theta) is0, ie when the velocity and magnetic field are in the same direction(angle is 0^o)