Physics

Problem

Which of the following expressions correctly gives the magnitude of the magnetic field

B

at the centre of a single circular loop of radius

R

carrying current

I

? (

\mu_0

is the permeability of free space.) a)

B = \dfrac{\mu_0 I}{R}

B = \dfrac{\mu_0 I}{2\pi R}

B = \dfrac{\mu_0 I}{2R}

B = \dfrac{\mu_0 I}{4\pi R}