JEE Main20199 Apr 2019Evening ShiftPhysicsMagnetic Effects of CurrentActual
A moving coil galvanometer has a coil with 175 turns and area 1 c m 2 . It uses a torsion band of torsion constant 10 - 6 N m / r a d The coil is placed in a magnetic field B parallel to its plane. The coil deflects by 1 o for a current of 1 m A The value of B (in tesla) is approximately:
Options
- A10 - 2
- B10 - 4
- C10 - 3
- D10 - 1
Correct answer
C. 10 - 3
Step-by-step solution
For a moving coil galvanometer. τ = i A N B = c θ B = c θ i A N = 1 0 - 6 1 0 - 4 × 175 × 1 0 - 3 × π 180 B ≈ 1 0 - 3 T