# Moving Charges and Magnetism: Lorentz Force, Cyclone Frequency (For CBSE, ICSE, IAS, NET, NRA 2022)

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## Lorentz Force

- When the total force on a charge c which is moving with a velocity v in the presence of electric field E and magnetic field B is termed as the lorentz force.
- The Lorentz Force is the force on a charged particle due to electric and magnetic fields.
- A charged particle in an electric field will always feel a force due to this field.
- A charged particle in a magnetic field will only feel a force due to the magnetic field if it is moving relative to this field.

F = | force |

q = | electric charge |

E = | external electric field |

v = | velocity |

B = | magnetic field |

## Cyclone Frequency

- A charge c completes a circular orbit on a plane normal to B which is the uniform magnetic field.
- Uniform circular motion frequency is known as cyclone frequency. This frequency is unaffected by the radius and speed of the particle.
- It can be determined with the help of a machine known as cyclotron which is used to accelerate the particles which are charged.

## Biot-Savart Law

In this law magnetic field dB due to the presence of an element dl which is carrying a continuous flow of current I at the point P at a distance r from the current element is to obtain a total field at P and integration of this vector expression over the entire length of the conductor.

## Ampere՚s Circuital Law

- According to this law, an open surface S if bounded by a loop C, then the current I passing through S
- The sign of I is determined by the right-hand rule.
- Non-parallel currents repel and parallel currents attract each other.