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A moving coil galvanometer has a coil with 175 turns and area 1 cm 2 . It uses a torsion band of torsion constant 10 –6 N-m/rad. The coil is placed in a magnetic field B parallel to its plane. The coil deflects by 1° for a current of 1 mA. The value of B (in Tesla) is approximately :

1. 10 –3
2. 10 –1
3. 10 –4
4. 10 –2

Correct answer: 10 –3

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