Force on Moving Charge in Magnetic Field

When a charged body moves in a magnetic field, it experiences a force. Such a force experienced by a moving charge is called the Lorentz force. The Lorentz force on a particle with a charge +q moving with a velocity v in a magnetic field B is given by

F = q (v × Β)

|F|= q v B sin θ

where θ is the angle between the directions of v and B. The direction of F is given by Fleming’s left hand rule.

Fleming’s Left Hand Rule

Fleming’s left hand rule states that if you stretch the fore finger, the central finger and the thumb of your left hand at right angles to each other and hold them in such a way that the fore finger points in the direction of magnetic field and the central finger points in the direction of motion of positively charged particle, then the thumb will point in the direction of the Lorentz force.