Key Points of Electromagnetic Induction

 Some key points to be remembered from Class 12 Physics Chapter Electromagnetic Induction:

1. Electromagnetic induction is the phenomenon of the production of an electromotive force (emf) in a closed circuit due to a change in the magnetic flux linked with the circuit.
2. Faraday's law of electromagnetic induction states that the emf induced in a circuit is directly proportional to the rate of change of magnetic flux linked with the circuit.
3. Lenz's law states that the direction of the induced emf is such that it opposes the change in magnetic flux that produced it.
4. The magnetic flux is the product of the magnetic field strength, the area of the loop, and the cosine of the angle between the magnetic field and the normal to the loop.
5. The emf induced in a conductor can be calculated using the formula emf = -N(dΦ/dt), where N is the number of turns in the coil, and dΦ/dt is the rate of change of magnetic flux through the coil.
6. A transformer is a device used to change the voltage level of an alternating current (AC). It consists of two coils of wire, the primary and the secondary, which are magnetically linked.
7. The ratio of the number of turns in the primary coil to the number of turns in the secondary coil is called the turns ratio. The voltage ratio is equal to the turns ratio.
8. The transformer operates on the principle of electromagnetic induction, where an AC current in the primary coil produces an alternating magnetic field, which induces an emf in the secondary coil.
9. The efficiency of a transformer is the ratio of the output power to the input power.
10. An AC generator is a device used to convert mechanical energy into electrical energy. It operates on the principle of electromagnetic induction, where a coil of wire rotates in a magnetic field, producing an emf in the coil.
11. The frequency of the AC output of the generator is determined by the speed of rotation of the coil and the number of turns in the coil.
12. An inductor is a device used to store energy in a magnetic field. It consists of a coil of wire that produces a magnetic field when a current flows through it.