This knowledge of electricity is a physical content that high school students must master, and it is often encountered in the college entrance examination. The following are the knowledge points of physics and electricity in high school that I brought to you, hoping to help you.

High school physics and electrical knowledge points 1. Basic law of electric field

1, law of conservation of charge: charge will neither be created nor destroyed, but it can only be transferred from one object to another, or from one part of an object to another, and the total amount of charge remains unchanged during the transfer process. (1) Three charging modes: friction charging, induction charging and contact charging.

(2) Meta-charge: the smallest charged unit. The charge of any charged body is an integer multiple of meta-charge, e= 1.6? 10- 19C Millikan measured the value of e.

2. Coulomb's Law

Law content (1): The interaction force between charges at two stationary points in vacuum is directly proportional to the product of their charges and inversely proportional to the square of their distance, and the direction of the interaction force is on their connecting line.

(2) Expression: k=9.0? 109N？ M2/C2 electrostatic force constant

(3) Applicable conditions: static point charge in vacuum.

Second, the nature of electric field energy

1, the basic property of electric field energy: the charge moves in the electric field, and the electric field force should do work on the charge.

2. potential?

(1) Definition: the ratio of the potential energy Ep of a point charge in an electric field to the amount of charge.

(2) Definition:? Unit: Volts (V) Signed calculation.

(3) Features:

○ 1 potential is relative, relative to the reference point. But the difference of potential has nothing to do with the choice of reference point.

○2 potential is scalar, but it has positive and negative sign. The sign only indicates whether the potential at this point is higher or lower than that at the reference point.

○3 The electric potential is determined by the electric field itself and has nothing to do with Ep and Q. ..

○4 The potential is numerically equal to the work done by the electric field force when the unit positive charge moves from this point to the zero potential point.

(4) the method of judging the potential level

○ 1 According to the electric field line, the potential decreases along the electric field line. ? A & gt？ B

2 According to the electric potential energy:

Positive charge: large potential energy and high potential; Small potential energy, low potential.

Negative charge: large potential energy and low potential; Small potential energy, high potential.

Conclusion: Only under the action of electric field force can electrostatic charge move from the place with high electric potential energy to the place with low electric potential energy.

3. Potential energy Ep

(1) Definition: Due to the interaction between electric field and charge, the energy of charge in electric field is determined by its position. The electric potential energy of a charge at a certain point is equal to the work done by the electric field force to move the charge from that point to the zero potential energy position.

(2) Definition formula: signed calculation

(3) Features:

○ 1 electric potential energy is relative. Relative to the zero potential energy surface, the earth or the zero potential energy surface at infinity is usually selected.

○2 The change of electric potential energy △Ep has nothing to do with the choice of zero potential energy surface.

4. Potential difference UAB

(1) Definition: potential difference between two points in an electric field. Also known as voltage.

(2) Definition: UAB=? A-? B

(3) Features:

○ 1 potential difference is scalar, but it has a sign, and the sign only indicates who has higher or lower potential at the starting point and the end point. If UAB>；; 0, then UBA.

2 units: Volts

○3 The potential difference between two points in the electric field is certain and has nothing to do with the choice of zero potential plane.

○4U=Ed formula for calculating potential difference between two points in uniform electric field. Relationship between potential difference and electric field strength.

5, electrostatic equilibrium state

(1) Definition: The charge in a conductor has no steady state of directional motion.

(2) Features

○ 1 The internal field strength of the conductor in electrostatic balance is zero everywhere.

○2 The electric field generated by the induced charge at any position in the conductor is equal to and opposite to the external electric field there.

3 The whole conductor in electrostatic balance is an equipotential body, and the surface of the conductor is an equipotential surface.

○4 The charge is only distributed on the outer surface of the conductor, and the distribution of the conductor surface is related to the bending degree of the conductor surface. The more bends, the more charge distribution.

6. Electric field force does work, WAB

(1) Characteristics of electric field force doing work: The electric field force doing work has nothing to do with the path, but only with the initial and final positions, that is, with the potential difference between the initial and final positions.

(2) Expression: WAB=UABq? Signed calculation (applicable to any electric field)

WAB=Eqd？ Distance along the direction of electric field. uniform electric field

(3) The relationship between work done by electric field force and electric potential energy.

WAB =-△Ep = EPA -EPB

Conclusion: The electric field force does positive work and the electric potential energy decreases.

The electric field force does negative work and the electric potential energy increases.

7, equipotential surface:

(1) Definition: A surface composed of points with equal potential.

(2) Features:

○ 1 The potentials of all points on the equipotential surface are equal. If the charge moves on the equipotential surface, the electric field force will not do work.

The equipotential surface is perpendicular to the electric field line.

3 Two equipotential surfaces do not intersect.

○4 The density of equipotential surface indicates the magnitude of field strength: sparse and weak, dense and strong.

5 When drawing equipotential surfaces, the potential difference between adjacent equipotential surfaces is equal.

(3) Judging the potential difference between two points on the electric field line: the potential difference between two points close to the field source (strong field) is greater than that between two points at the same distance from the field source (small field strength).

Third, the nature of electric field force.

1, the basic property of electric field: electric field has a powerful effect on the charge put into it.

2. electric field intensity e

(1) Definition: The ratio of the electric field force F of a charge at a certain point in the electric field to the charge quantity Q of the charge is called the electric field strength at that point.

(2) Definition: E has nothing to do with F and Q, but is determined by the electric field itself.

(3) Electric field strength is vector: size: electric field force per unit charge.

Direction: specifies the direction of positive charge, and the direction of negative charge is opposite to E.

Click the next page to share more summary of high school physics and electrical knowledge points.