What is the direction of the electric field line, give me an example, thank you

To interpret the direction of electric field lines, it is necessary to know what an electric field line is. In order to visually describe the distribution of the electric field, the electric field lines introduce some imaginary curves into the electric field. The tangent direction of each point on the curve is the same as the direction of the electric field strength of the point; The field strength is strong where the curve is dense, and the field strength is weak where the curve is sparse.

In any electric field, the field strength of each point p has a certain direction. Based on this, we can draw a series of curves in the electric field, so that the tangent direction of each point on the curve is consistent with the direction of the field strength of that point, and these lines are called electric field lines. This is our practical application.

The electric field line is marked with an arrow, indicating the positive direction that the tangent of each point on the line should take (i.e., the direction of the field strength of that point). Using electric field lines, the direction of the field strength at each point through which it passes can be determined, and thus the direction of the electric field force on a positive charge placed at that point can be expressed.

First of all, you have to know that the positive and negative charges, they are like mountains and valleys, and the magnitude of the electric potential is like the height of the terrain, the electric field lines are like water, and the direction of the electric field lines is the direction of the river from the high (high potential) to the low place.

Hope you understand!!

The tangent direction of a point of the electric field line is the direction of the electric field at that point.

Electric field lines are some imaginary curves introduced into the electric field in order to visually describe the distribution of the electric field. The tangent direction of each point on the curve is the same as the direction of the electric field strength of the point; The field strength is strong where the curve is dense, and the field strength is weak where the curve is sparse.

Electric field line properties of electrostatic fields.

1) The electric field lines are not closed, starting from a positive charge or infinity and ending at infinity or a negative charge;

2) the electric field lines are perpendicular to the surface of the conductor;

3) The electric field lines are perpendicular to the equipotential surface.

A method for judging the direction of electric field strength

1. Electric field line.

The tangent direction of a point along the direction of the electric field line is the direction of the electric field strength of that point. The tangent direction of any point on the electric field line, that is, the direction of the electric field strength at that point. So, if we know the electric field line distribution map, we can determine the direction of the electric field at any point.

2. The direction of the electric field force on the charge is judged.

According to the direction of the positive charge receiving electric field force and the direction of the electric field strength are the same, the direction of the negative charge receiving electric field is opposite to the direction of the electric field strength. Physically, it is stipulated that in an electric field, the direction of the electric field force experienced by a positive charge is the same as that of the electric field; The direction of the electric field force on which the negative charge is subjected is opposite to the direction of the electric field there. That is, the direction of the electric field force must be in the same straight line as the direction of the electric field, either in the same direction or in the opposite direction.

3. Equipotential surface.

The direction of electric field intensity is the direction in which the electric potential decreases the fastest in the electric field, and the equipotential surface is drawn, and the electric field lines are perpendicular to the equipotential surface. From the relationship between the electric field lines and the equipotential surface, it can be seen that the electric field lines are always perpendicular to the equipotential surface, and the electric potential decreases along the direction of the electric field. However, the direction of the electric potential decrease is not necessarily the direction of the electric field, but the direction of the electric field strength that should be measured by the surface field Hengda as the direction of the electric potential reduction speed (the largest potential difference per unit distance).

4. Field source charge method.

In the electric field around the positive field source charge, the direction of the electric field is diverging from the positive field source charge; In the electric field around the negative field source charge, the direction of the electric field is directed towards the negative field source charge.

Electric Field Lines: A visual method of describing the electric field, where the tangent direction of each point on the line is consistent with the direction of the field strength at that point.

Function: The tangent direction indicates the direction of the field strength, and the density indicates the magnitude of the field strength.

Features: Begins with a positive charge and ends with a negative charge, does not close the age, does not intersect.

Note: The electric field line is a kind of curve that is artificially drawn to vividly represent the distribution of the electric field, and the experiment only simulates the shape of this curve, and the actual electric field does not have such a curved and stuffy line, and the experiment does not confirm the existence of such a line.

Electric field direction with positive charge.

The direction of force is the same. The characteristic of the electric field is that there is a force acting on the charge, i.e., the electric field force.

The positive charge is subjected to the same direction as the electric field, and the negative charge is subjected to the opposite direction of the electric field.

In order to vividly describe the distribution of field strength, some directional curves are artificially drawn in the electric field, and the tangent of a point on the curve is drawn.

The direction indicates the direction of the field strength at that point. Electric field lines.

The denser the electric field, the stronger the electric field.

The larger. <>

Calculations

The electric field strength at a point in the electric field is numerically equal to the electric field force experienced by the unit charge at that point. The electric charge and volume of the test charge should be small enough to ignore its influence on the electric field distribution and accurately describe the electric field at each point.

The field strength is a vector quantity whose direction is positive and the direction of the force on the test charge is equal to the force experienced by the unit test charge. The unit of field strength is volt-meter, and 1 volt-meter = 1 bullhouse. The spatial distribution of field strength can be illustrated by the image of the electric field line.

Refer to the above content: Encyclopedia - Electric Field Strength.

Problem 1: Physics. How to determine the direction of the electric field line?

Let the point charge move from P to Q, and make a perpendicular line of the C equipotential surface through the P point, it can be seen from the bending of the trajectory that the direction of the electric field force is perpendicular to the C equipotential facing downward, and in the process of moving from P to Q, the electric field force does positive work, the electric potential energy decreases (B is correct), the kinetic energy increases (C is wrong), and the point charge is positively charged, so the potential difference between the two points of Pq is greater than zero, so the potential of P point is greater than the potential of point Q, and the A term is wrong. The density of the equal-potential surface can indicate that the field strength is small, so the field strength at p is stronger than the field strength at point Q, so the electric field force of the early shed front at point P is larger, and the acceleration is greater. Item d is correct.

Question 2: How to judge the direction of the electric field line The bending direction is the direction of the force, and the direction of the electric field is judged according to the charge properties, the positive charge is along the direction of the electric field line, and the negative charge is opposite.

Question 3: How to judge the direction of the electric field line? In an active field, a positive charge is directed to infinity or a negative charge, and in a passive field, it is judged by Lenz's law. In an active field, a point is directionally perpendicular to an equipotential surface, and in a passive field, it is distributed in a circle.

Question 4: How to judge what electricity particles carry according to the direction of the motion trajectory and electric field lines 1. The trajectory of charged particles is a straight line.

Accelerating motion in the direction of the electric field line, the charged particles are positively charged; Do a deceleration motion, and the charged particles are negatively charged. Negatively charged particles that move at an accelerated pace against the direction of the electric field line; Do a deceleration motion, and the charged particles are positively charged.

If the direction of motion of the charged particle and the direction of the electric field line are the same, then the particle is positively charged, and if the direction of the particle's motion and the direction of the electric intensity are opposite, then the particle is negatively charged.

2. The trajectory is curved

Look at the direction of the curve. The direction of the resultant force must be directed to the inside of the curve (the direction of bending).

The resultant force is positively charged along the direction of the electric field line, and negatively charged in the direction of the electric field line.

Question 5: How to judge the direction of the electric field The direction of the electric field strength can be judged by the direction of the electric field force on the charge: the direction of the electric field force on the positive charge is consistent with the direction of the field strength at the point, and the direction of the electric field force on the negative charge is opposite to the direction of the field strength at the point.