Task 2.2.
At the tops of a square with a side of 0.5 m there are charges of the same size. In the case where two adjacent charges are positive and the other two are negative, the field strength at the center of the square is 144 V / m. Determine the charge.

Task 2.12
In the field of an infinite uniformly charged plane with a surface charge density of 10 μC / m2, a charge moves from a point 0.1 m away from the plane to a point 0.5 m away from it. Determine the charge, if the work is done 1 mJ.

PROBLEM 2.22
Calculate the capacity of a battery consisting of three 1 μF capacitors each, in all possible cases of their connection.

Task 2.32
Determine the density of the current flowing through a conductor 5 m long if a potential difference of 2 V is maintained at its ends. The resistivity of the material is 2 μΩ • m.

Task 2.42
For two infinitely long rectilinear parallel conductors, the distance between them is 15 cm, the currents 4 and 6 A flow in one direction. Determine the distance from the conductor with a smaller current to the geometrical location of the points at which the magnetic field strength is zero.

Problem 2.52
Two parallel infinitely long conductors with currents of 10 A interact with a force of 1 mN per 1 m of their length. At what distance are the conductors?

PROBLEM 2.62
Perpendicular to the lines of induction of a homogeneous magnetic field by induction of 1 mT along two parallel conductors, a 20 cm long bridge moves without friction. When the circuit containing this bridge is closed, a current of 0.01 A flows in it. Determine the speed of motion of the commutator. The resistance of the circuit is 0.1 ohms.

Task 2.72
By the condition of Problem 71, find the energy of the magnetic field of the solenoid, if its length is 20 cm, and the diameter is 4 cm.