Question

Answer it please it's urgent​

Answer 1

Answer:

b is the correct option

Explanation:

Ampere's Circuital Law states the relationship between the current and the magnetic field created by it. This law states that the integral of magnetic field density (B) along an imaginary closed path is equal to the product of current enclosed by the path and permeability of the medium.

Answer 2

According to Ampere's circuital law, (b) ∫ B . dl = μο I

What is Ampere's circuital law?

• The law states that 'the line integral for a closed curve is equal to μο times the net current I passing through the area bounded by the curve.'
• It can be derived using the Biot-Savart law.

Derivation of Ampere's circuital law:

Consider a wire carrying a current I producing a magnetic field B in form of concentric circles around it.

Consider an amperian loop of radius r with the wire at its center.

Net magnetic field due to the loop is given by :

∫B.dl = ∫B dl cosФ

Since Ф=0° ⇒ cosФ = 1

∫B.dl = ∫B dl

= B∫dl

= $B[L]^{2\pi r} _0$

= B [ 2πr - 0]

∫B.dl = B.2πr         - (1)

Using Biot-Savart law, we know that magnetic field at the center of wire = μοi/2πr          -(2)

Putting (2) in (1),

∫B.dl = μοi/2πr  X  2πr  

= μοi

Hence, ∫B.dl= μοi