18. Direct infinite current I1 = 5A and a rectangular frame with a current I2 = 3A in the same plane so that the side of the frame l = 1 m parallel to the direct current and is separated from it by a distance r = 0,1 b, where b - the length of the other side of the frame. Determine what kind of work you need to make in order to rotate the frame at an angle α = 90 ° relative to the axis OO1, parallel direct current passing through the middle of the opposite sides of the frame b.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)