Electromagnetism

Step 1: Definition.
When current in a coil changes, an emf is induced in the coil itself (self-induced emf).
Step 2: Formula.
where is the coefficient of self-induction.
Step 3: Conclusion.
Thus,

Case (i): Along the electric field.
Force on charge: , acts in the direction of motion. Particle accelerates uniformly along a straight line. Case (ii): Perpendicular to the electric field.
Force acts perpendicular to velocity, causing constant acceleration in one direction and uniform motion in the other. Resulting path is a parabola. Case (iii): Perpendicular to the magnetic field.
Force acts perpendicular to both velocity and . This causes uniform circular motion with radius . Case (iv): Along the magnetic field.
Force , since is parallel to . Hence the particle moves in a straight line with constant velocity. Case (v): In crossed electric and magnetic fields ( ).
- Electric field provides linear acceleration. - Magnetic field provides circular motion. - Resultant path is a helix (spiral).
Step 6: Conclusion.
The nature of path depends on field configuration: linear, parabolic, circular, or helical.