A small coil is introduced between the poles of an electromagnet so that its axis coincides with the magnetic field direction. The cross-sectional area of the coil is equal to `S = 3.0 mm^2`, the number of turns is `N = 60`. When the coil turns through `180^@` about its diameter, a galvanometer connected to the coil indicates a charge `q = 4.5muC` flowing through it. Find the magnetic induction magnitude between the poles, provided the total resistance of the electric circuit equals `R = 40 Omega`.

Explanation

To solve the problem, we will use the formula for induced charge in a coil rotating in a magnetic field:

\[ Q = -\frac{N B A}{R} (\cos \theta_2 - \cos \theta_1) \]

Where:
- \( Q \) = induced charge (in coulombs)
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