This question was previously asked in

ESE Electrical 2015 Paper 1: Official Paper

Option 4 : Ampere’s law

NTPC Diploma Trainee 2020: Full Mock Test

12115

120 Questions
120 Marks
120 Mins

__CONCEPT__:

- Ampere’s Law: Line integral of the magnetic field B around any closed curve is equal to μ0 times the net current I threading through the area enclosed by the curve i.e.

\(\oint \vec B \cdot \overrightarrow {dl} = {\mu _o}I\)

where I - current flowing

__EXPLANATION__:

- In a simplified form, Ampere's circuital law states that if the field is directed along the tangent to every point on the perimeter L of a closed curve and its magnitude is constant along the curve, then BL = μoI

where I = the net current enclosed by the closed circuit.

- The closed curve is called the Amperean loop which is a geometrical entity and not a real wire loop.

- According to this law, magnetic fields are related to the electric current produced in them.
- The law specifies the magnetic field that is associated with a given current or vice-versa, provided that the electric field doesn’t change with time.
- It can be applied outside the conductor only.