The magnetic field due to a current carrying circular loop of radius 6 cm at a point on the axis at a distance 8 cm from the centre is 216 μT. What will be its value at the centre of the loop ?

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(2) 1000 μT. Given: R=6 cm, x=8 cm and Bₐₓᵢₛ=216 μT. Idea: on the axis B=(μ₀ I R²)/(2(R²+x²)^3/2) and at the centre B₀=(μ₀ I)/(2R); taking the ratio cancels μ₀ and I, which are never given. (B₀)/(Bₐₓᵢₛ)=((R²+x²)^3/2)/(R³). R²+x²=36+64=100, so (R²+x²)^3/2=1000 while R³=216. B₀=216×(1000)/(216)=1000 μT.

The magnetic field due to a current carrying circular loop of radius 6 cm at a point on the axis at a distance 8 cm from the centre is 216 μT. What will be its value at the centre of the loop ?

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