Task 2.3
At the tops of the square with a side of 0.1 m, charges of 0.1 nC are placed. Determine the strength and potential of the field in the center of the square, if one of the charges differs in sign from the others.

Task 2.13
What kind of work needs to be done to make the charges 1 and 2 nC, located at a distance of 0.5 m, close to 0.1 m?

Task 2.23
The charge on each of two series-connected capacitors of 18 and 10 pF is equal to 0.09 nC. Determine the voltage:
A) on the battery of capacitors;
B) on each capacitor.

PROBLEM 2.33
The voltage at the ends of the conductor with a resistance of 5 ohms for 0.5 s gradually increases from 0 to 20 V. What is the charge passing through the conductor during this time?

Task 2.43
Solve problem 42 for the case when currents flow in opposite directions.

Task 2.53
Find the radius of the proton trajectory in a magnetic field with an induction of 2.5 T if it moves perpendicular to it and has a kinetic energy of 3 MeV.

Task 2.63
An electromotive force of induction of 0.06 V appears on the ends of the aircraft wings with a span of 20 m, flying at a speed of 900 km / h. Determine the vertical component of the Earth's magnetic field strength.

Task 2.73
A current of 1 A flows through a solenoid 0.25 m long having a number of turns 500. The cross-sectional area is 15 cm2. An iron core is inserted into the solenoid. Find the energy of the magnetic field of the solenoid. The dependence B = f (H) is shown in Fig. 4.