Question

A wire carrying a current is shaped in the form of a circular loop of radius 4.0 mm. If the magnetic field strength at its center is 1.1 mT with no external magnetic fields contributing to it, what is the magnitude of the current that flows through the wire? A) 17 A B) 28 A C) 14 A D) 7.0 A

Answer 1

Answer:D) 7.0 A

Explanation:

The magnetic field strength at the center of a circular loop  is calculated using the formulae

B = μ₀I / 2R

where B = ,magnetic field strength= 1.1mT = 1.1 X 10^-3T

μ₀=  magnetic constant or the permeability of free space=4π X 10^-7 H/m

R = radius = 4.0mm =4.0 x 10^-3m

I= Current = ?

B=μ₀I / 2R

I = B2R /μ₀

I =   1.1 X 10^-3T X 2 X 4.0 x 10^-3m / 4π X 10^-7 H/m

I =7.00 A

Therefore magnitude of the current that flows through the wire is 7.0 A