A 100-m long wire carrying a current of 4.0 A will be accompanied by a magnetic field of what strength at a distance of 0.040 m from the wire? (magnetic permeability in empty space µ₀ = 4π × 10−⁷ T⋅m/A) A) zero B) 1.6 × 10−⁵ T C) 2.0 × 10−⁵ T D) 4.0 × 10−⁵ T

Question

Quizplus · Accepted Answer

The magnetic field at a distance r from a long wire with current I can be calculated using the formula:

B = μ₀I/2πr

where μ₀ is the magnetic permeability in empty space, I is the current in the wire, and r is the distance from the wire.

Substituting the given values, we get:

B = (4π × 10−7 T⋅m/A)(4.0 A)/2π(0.040 m)
B = 2.0 × 10−5 T

Therefore, the answer is (C) 2.0 × 10−5 T.

A 100-M Long Wire Carrying a Current of 4