Law of conservation of mechanical energy: mgh1+mv12/2 = mgh2+mv22/2.
The mathematical expression of Coulomb's law: F=kQq/r2.
Definition of electric field strength: e = f/q.
Definition of potential difference: u = w/q.
Ohm's law: I = u/r.
Calculation of electric power: P=UI.
Joule's law: Q=I2Rt.
Definition of magnetic induction intensity: B=F/IL.
The formula of ampere force is F=BIL.
The formula of Lorentz force: f=qvb.
Faraday's law of electromagnetic induction: e = Ф Ф/Ф t.
Induced electromotive force generated by conductor cutting magnetic induction line: E=Blv.
Common methods of physics multiple-choice questions:
① Screening (elimination) method: According to the information in the topic and the knowledge you have, from easy to difficult, gradually eliminate unreasonable options and finally approach the correct answer.
② Special value (special case) method: let some physical quantities take special values and make judgments through simple analysis and calculation. Only applicable to multiple-choice questions that can exclude the rest of the wrong options after substituting special values in each option.
(3) Limit analysis method: a method that limits some physical quantities and draws conclusions.