Question

State Biot-Savart’s law.

Answer 1

The magnitude of magnetic field d`vec"B"` at a point P at a distance r from the small elemental length taken on a conductor carrying current varies-

1. directly as the strength of the current I
2. directly as the magnitude of the length element `vec"dl"`
3. directly as the sine of the angle (say,θ) between `vec"dl"` and `hat"r"`.
4. inversely as the square of the distance between the point P and length element `vec"dl"`. This is expressed as `"dB" prop ("Id"l)/"r"^2` sin θ