A small coil C with N = 200 turns is mounted on one end of a balance beam and introduced between the poles of an electromagnet as shown in Fig. 3.70. The cross-sectional area of the coil is S = 1.0 cm2, the length of the arm OA of the balance beam is l = 30 cm. When there is no. current in the coil the balance is in equilibrium. On passing a current I = 22 mA through the coil the equilibrium is restored by putting the additional, counterweight of mass ∆m = 60 mg on the balance pan. Find the magnetic induction at the spot where the coil is located.

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