Fleming’ s left Hand Rule
If we stretch the thumb, the forefinger and the central finger if left hand in such a way that all three are perpendicular to each other, then if forefinger represents the direction of magnetic field, central finger represents the direction of current flowing through the conductor, then thumb will represent the direction of magnetic force.
Lorentz Force
The total force experienced by a charge moving inside the electric and magnetic fields is called Lorentz force. It is given by F = q( E * v * B)
Motion of a Charged Particle in a Uniform Magnetic Field When charged particle enter normal to the magnetic field it follows a circular path.
The radius of the path, r = mv / Bq
∴ r ∝ mv and r ∝ 1 /( q / m)
Time period, T = 2πm / Bq
When charged particle enter magnetic field at any angle except 90 °, then it follows helical path.
The radius of the path, r = mv sin θ / Bq
The distance travelled by the charged particle in one time period due to component of velocity v cos θ, is called pitch of the path
Pitch = T * v cos θ = 2πmv cos θ / Bq