Card 3

1.     Write down the main points in the notebook.

Electrical field strength. Quantitative characteristic power action of an electric field on charged body serves as the vector magnitude E, called an electric field.

E = F / q _пр.

It is determined by the ratio of forces F, the current from the field on pinpoint test charge q_пр, placed in the considered point fields to this charge.

The concept of "test charge" suggests that this charge is not involved in the creation of an electric field and so small that it does not distort it, i.e. it does not cause the redistribution of the charge space, creating a field in question. In SI, the unit of tension serves 1 V/m, which is equivalent to 1 N/kg.

The field strength of a point charge. Using the Coulomb law, find an expression for the electric field intensity produced by the point charge q in a homogeneous isotropic Wednesday at distance r from the charge:

In this formula, r – radius - vector connecting the charges q и q_пр. From the last formula follows that tension E the field of a point charge q at all points of the field is directed radially from the charge when q > 0 and to charge when q < 0.

Task 2 (do this in your notebook).

A point charge of 27 nC is given.

А) Determine the field strength at a distance of 3 cm, 6 cm, 9 cm, 12 cm, 15 cm from the charge. Each pair counts only, for one to collect in the table.

B) Build a chart

C) Build a graph of the dependence of tension on the distance

D) Draw a charge field using lines.

E) Compare the results with the pictures in slide 11.

1.     Write down the main points in the notebook.

Electrical field strength. Quantitative characteristic power action of an electric field on charged body serves as the vector magnitude E, called an electric field.

E = F / q _пр.

It is determined by the ratio of forces F, the current from the field on pinpoint test charge q_пр, placed in the considered point fields to this charge.

The concept of "test charge" suggests that this charge is not involved in the creation of an electric field and so small that it does not distort it, i.e. it does not cause the redistribution of the charge space, creating a field in question. In SI, the unit of tension serves 1 V/m, which is equivalent to 1 N/kg.

The field strength of a point charge. Using the Coulomb law, find an expression for the electric field intensity produced by the point charge q in a homogeneous isotropic Wednesday at distance r from the charge:

In this formula, r – radius - vector connecting the charges q и q_пр. From the last formula follows that tension E the field of a point charge q at all points of the field is directed radially from the charge when q > 0 and to charge when q < 0.

Task 2 (do this in your notebook).

A point charge of 27 nC is given.

А) Determine the field strength at a distance of 3 cm, 6 cm, 9 cm, 12 cm, 15 cm from the charge. Each pair counts only, for one to collect in the table.

B) Build a chart

C) Build a graph of the dependence of tension on the distance

D) Draw a charge field using lines.

E) Compare the results with the pictures in slide 11.

Task 3.

1. The figure shows the lines of the electric field created by two oppositely charged plates.

A) Which lines (dashed or solid) are field lines of force? Explain the answer.

B) Select areas in the picture where the field, in your opinion, is uniform, non-uniform. Explain the answer.

C) Describe how the field strength varies when moving from the center of the pattern to the left edge. Explain the answer.

2. Figures A and B show point charges. Determine the field strength at points A, B and C. Show the direction of the intensity vector in each case. Select a scale for the tension vector.

А) В)

C) Calculate with what force the first charge field (case A) will act on a -4 nC charge placed at point B.

D) What kind of charge was placed at point C (case B) if the field acts on it with a force of 30 μC directed to the right in the plane of the figure.

3. A charge of 4 nC was placed in a uniform electrostatic field. What is the field strength if the field acts on it with a force of 36 μN?

Task 3.

1. The figure shows the lines of the electric field created by two oppositely charged plates.

A) Which lines (dashed or solid) are field lines of force? Explain the answer.

B) Select areas in the picture where the field, in your opinion, is uniform, non-uniform. Explain the answer.

C) Describe how the field strength varies when moving from the center of the pattern to the left edge. Explain the answer.

2. Figures A and B show point charges. Determine the field strength at points A, B and C. Show the direction of the intensity vector in each case. Select a scale for the tension vector.

А) В)

C) Calculate with what force the first charge field (case A) will act on a -4 nC charge placed at point B.

D) What kind of charge was placed at point C (case B) if the field acts on it with a force of 30 μC directed to the right in the plane of the figure.

3. A charge of 4 nC was placed in a uniform electrostatic field. What is the field strength if the field acts on it with a force of 36 μN?