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

Options

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

Answer

A

Explanation

`B_x=mu_0/(4pi) i/r(sin37^@+sin37^@)`
`B_x=(mu_0NiR^2)/(2(R^2+x^2))` and `B_c=(mu_0Ni)/(2R) crarr` centre.