State Faraday's laws of electromagnetic induction

Faraday’s laws of Induction

First law: -

• According to the first law an emf is induced in the circuit whenever the amount of magnetic flux linked with a circuit changes.
• Current was induced because of magnetic flux, as there is some current in the circuit therefore there will be some emf flowing in the circuit.
• Whenever the amount of magnetic flux linked with the circuit changes only at that time emf is induced.
• The induced emf will be there till there is change in the flux.
• When the magnet was moved then only there was change in the flux.
• As the magnet is moving the number of magnetic lines crossing the area is also changing.
• There is a change in the flux therefore there is induced emf.
• If the magnet is not moving, there will be no change in the amount of magnetic flux so there is no induced current.

Second law: -

• According to the second law the magnitude of the induced emf in a circuit is equal to the time rate of change of magnetic flux through the circuit.
• Emf which is induced will depend upon rate at which the magnetic flux is changing.
• Mathematically:-
  • Let Φ₁ = flux at initial time t=0.
  • Φ₂ = flux after time t.
  • Rate of change of flux=(Φ₂ – Φ₁)/t =dΦ/dt
• According to Faraday’s law:-
  • Induced emf e ∝ (dΦ/dt)
  • Experimentally the constant of proportionality was found to be 1 in all cases.
• Therefore e=(dΦ/dt)
  • Consider a coil which has N number of turns;Therefore
  • e = N(dΦ/dt)