Question

White Ampere's circuital law ? Obtain an expression for the magnitic field due to a long straight current carrying conductor using Ampere's circuital law.​

Answer 1

Answer:

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The Amperian loop is traced in the anticlockwise sense, so that the current I is taken as positive in accordance with the right hand rule. By Ampere's law, in free space, ∮→B⋅→dl=μ0I, where μ0 is the permeability of free space. This is the required expression.

Answer 2

Explanation:

Let MN be a long straight wire carrying current and P a point at distance

′

a

′

from wire where magnetic field B has to be found

using Ampere's circuital law, let us consider a circle element dl at P

⇒∮B.dl=μ

0

I

B is constant everywhere on the loop

⇒B∮dl=μ

0

I

⇒B×2πa=μ

0

I

⇒B=(

4π

μ

0

)×

a

2I