99 Percentile Qs Bank for JEE MainPhysicsMagnetic Effects of Current
A compass needle free to turn in a horizontal plane is placed at the centre of a circular coil of 30 turns and radius 12 cm . The coil is in a vertical plane making an angle of 45 ∘ with the magnetic meridian. The needle points west to east when the current in the coil is 0 .35 A . The horizontal component of the earth's magnetic field (in T ) at that location is
Options
- A3 . 9 × 10 - 5
- B3.9 × 10 - 6
- C5 × 10 - 5
- D2.6 × 10 - 5
Correct answer
A. 3 . 9 × 10 - 5
Step-by-step solution
Given, number of turns in the coil n = 30 Current in the coil I = 0.35 A Radius of circular coil = 12 cm = 0.12 m Let N - S be the line of magnetic of 45 o with the magnetic meridian. C 1 and C 2 be the plane of coil. The needle points west to east. The magnetic field produced due to the coil is B. The direction of B is along the axis of coil i.e., it makes an angle of 45 o with east. The needle points west to east only if the direction of magnetic field B is at 45 o from east. Use the formula, magnetic field produ