Faraday's law of electromagnetic induction
Faraday's law of electromagnetic induction is a law describing the magnitude and direction of self-induced electromotive force. It means that when the magnetic flux in the conductor changes, an electromotive force will be generated in the conductor, and its direction is proportional to the rate of magnetic flux change, but perpendicular to the direction of change. The mathematical expression of this law is: ε =-dφ/dt, where ε is the induced electromotive force, φ is the magnetic flux, and d/dt represents the derivative of time.
2. Lenz's Law
Lenz's law is a law describing electromagnetic induction. It shows that when the electromotive force appears in the conductor, the induced current will produce a magnetic field, and the direction of the magnetic field and the direction of the current meet the right-hand rule, that is, hold the conductor's right hand, point the thumb to the direction of the current, and the direction of the four fingers bending is the direction of the magnetic field. The mathematical expression of this law is: ε =-dφ/dt, where ε is the induced electromotive force, φ is the magnetic flux, and d/dt represents the derivative of time.
3. Self-induced electromotive force formula
Self-induced electromotive force refers to the electromotive force generated by current change. According to Faraday's law of electromagnetic induction, the magnitude of self-induced electromotive force is directly proportional to the current change rate, but perpendicular to the current change direction. The formula is: ε=-L(di/dt), where l is the self-inductance coefficient and di/dt is the current change rate.
4. Mutual inductance electromotive force formula
Mutual inductance electromotive force refers to the electromotive force generated between two or more coils due to the change of magnetic flux. According to Faraday's law of electromagnetic induction and Lenz's law, the magnitude of mutual inductance electromotive force is related to the change rate of magnetic flux and the number of coil turns. The formula is: ε=-M(dI 1/dt), where m is the mutual inductance coefficient and dI 1/dt is the current change rate in the coil 1.
To sum up, the above formula is an important formula in electromagnetic induction, in which Faraday's law of electromagnetic induction and Lenz's law are the basis, and on this basis, the formulas of self-induced electromotive force and mutual-induced electromotive force are derived. Mastering these formulas can help us to better analyze and solve related problems.