The moving coil of a galvanometer made of 200 turns of thin wire is suspended from an elastic thread. The area of the coil is 1 cm^2, it coincides in direction with the lines of induction of a magnetic field with induction of 15 mT. When the current of 5.0 A is passed through the coil it turns through 15^@. By what angle will the coil turn with a current of 7.5 muA? What is the torsion modulus of the thread?

The moving coil of a galvanometer made of 200 turns of thin wire is su

1.	The moving coil of a galvanometer made of 200 turns of thin wire is suspended from an elastic thread. The area of the coil is 1 cm^2, it coincides in direction with the lines of induction of a magnetic field with induction of 15 mT. When the current of 5.0 A is passed through the coil it turns through 15^@. By what angle will the coil turn with a current of 7.5 muA? What is the torsion modulus of the thread?
Answer» SOLUTION :A torque `M=wiSB` ACTS on the moving coil balanced by a torque M `f_(alpha)` DUE to the elasticity of the twisted thread, where is the torsion inodulus. Equating, we obtain `j alpha=W//SB` from which we see that, other conditions being equal, the coils angle of rotation is PROPORTIONAL to the CURRENT.

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