The magnetic field at a distance of 2 cm from a long straight current-carrying wire is 4 μT.What is the magnetic field at a distance of 4 cm from this wire?
A)2 μT
B)4 μT
C)6 μT
D)8 μT
E)10 μT

Question

Quizplus · Accepted Answer

The magnetic field created by a long straight current-carrying wire is given by:

B = μ0I/2πr

where B is the magnetic field at a distance r from the wire, I is the current flowing through the wire, and μ0 is the permeability of free space (4π × 10^-7 T·m/A).

Using the given information, we can solve for the current:

4 μT = μ0I/2π(0.02 m)

I = 2π(0.02 m)(4 μT)/μ0

I ≈ 10 A

Now we can use the above equation to find the magnetic field at a distance of 4 cm (0.04 m) from the wire:

B = μ0I/2πr = μ0(10 A)/2π(0.04 m) ≈ 2 μT

Therefore, the answer is A) 2 μT.

The Magnetic Field at a Distance of 2 Cm from a Long