Задача 31299.

In a uniform magnetic field perpendicular to the lines of induction is a flat loop area S = 1400 cm ^ 2. By maintaining a constant force in the loop current I = 12 A, it moved out of the field in the region of space where the field is zero. To determine the magnetic induction B, if you move the circuit was completed the work A = 0.2 J.

Detailed solution shorthand terms, formulas, laws used in the decision, the withdrawal of the calculation formula and the response.
If you have any questions to address, please. I´ll try to help.