# NAGALAND Class 12-science Physics Moving Charges and Magnetism

#### Magnetic Lorentz Force

Study Lorentz force acting on a charge moving in a magnetic field. Identify the trajectory of moving charge and work done by Lorentz force.#### Motion in Combined E and B Fields

Application of Lorentz force to design velocity selector. Study of the working principle of Particle Accelerator, that is, Cyclotron#### Biot Savart Law

State Biot-Savart Law. Apply right hand curl rule to find the direction of B due to straight current carrying and circular loop of wire.#### Ampere's Law

1. Ampereandrsquo;s law states that the line integral over a closed loop of the magnetic field produced by a current distribution I :

2. If B is directed along the tangent to every point on the perimeter L of a closed current loop, then according to Ampereandrsquo;s law : BL = andmicro;0I

#### The Solenoid and Toroid

1. A solenoid is a helical winding on a cylindrical core used to produce a nearly uniform magnetic field.

2. Magnetic field produced by solenoid is directly proportional to the number of turns of solenoid and is given as: B =m_{0}nI.

3. The magnetic field is zero inside and outside the toroid.#### Force on Current Carrying Wire

1. Parallel wires carrying current in the same direction attract and carrying current in the opposite directions repel.

2. 1 ampere is that steady current in each of two parallel wires of infinite length, 1 m apart in empty space, causes each wire to experience a force of exactly 2x10^{-7}N/m of length.#### Torque on Current Carrying Loop

Identify and study the forces and torque on current carrying loop placed in a uniform magnetic field