The magnetic field due to a current-carrying circular loop of radius `10cm` at its centre is `0*60xx10^-4T`. Find the magnetic field due to this loop at a point on the axis at a distance of `4cm` from the centre.

Answer

`4xx10^-5T`

Explanation

Here, `r=10cm=0*10, B_1=0*50xx10^-4T`,
`x=4cm=*04m`
Magnetic field at the centre of a cicular coil carrying current is
`B_1=(mu_0)/(4pi)(2piI)/(r)=(mu_0I)/(2r)`
Magnetic field due to circular current loop at a point on the axis of loop, distance x from the centre of loop is
`B_2=(mu_0)/(4pi)(2piIr^2)/((r^2+x^2)^(3//2))=(mu_0Ir^2)/(2(r^2+x^2)^(3//2))`
`:. B_2/B_1=(r^3)/((r^2+x^2)^(3//2))`
`=((0*10)^3)/([(0*1)^2+(0*04)^2]^(3//2))=0*8`
`B_2=B_1xx0*8=(0*50xx10^-4)xx0*8`
`=4xx10^-5T`