Question

A very long wire generates a magnetic field of 0.0070×10−4t at a distance of 1 mm . what is the magnitude of the current?

A) 2.0 mA B) 3100 mA C) 4000 mA D) 1.0 mA

Answer 1

Step-by-step explanation:

The magnetic field generated by a long straight wire can be calculated using Ampere's Law as follows:

B = (μ₀ * I) / (2π * r)

Where:

B is the magnetic field strength (0.0070 × 10^(-4) T),

μ₀ is the permeability of free space (4π × 10^(-7) T m/A),

I is the current,

r is the distance from the wire (1 mm = 0.001 m).

Rearranging the formula to solve for current (I):

I = (B * 2π * r) / μ₀

Substituting the given values:

I = (0.0070 × 10^(-4) T * 2π * 0.001 m) / (4π × 10^(-7) T m/A)

I ≈ 3107.96 A

After converting to milliamperes (mA):

I ≈ 3100 mA

So, the correct answer is:

B) 3100 mA