The magnetic field due to a current carrying loop of radius ` 3 cm` at a point on the axis at a distance of `4 cm` from the centre is ` 54 muT`. What will be its value at the centre of loop ?

Options

A. `250 muT`
B. `150muT`
C. `125 muT`
D. `75 muT`

Answer

A

Explanation

`(B_("centre"))/(B_("axis"))=(1+(x^(2))/(R^(2)))^(3//2) implies (B_("centre"))/54=(1+(4/3)^(2))^(3//2)=125/27`
`B_("centre")=250 muT`