Question

A wire is found on a long rod of material of relative permeability μᵣ = 4000 to make a solenoid if the current through the wire is 5A and number of turns per unit length is 1000 per metre in the magnetic field inside solenoid is

a. 25.12 mT
b. 12.56 mT
c. 12.56 T
d. 25.12 T

Answer 1

The magnetic field inside a solenoid with given parameters (relative permeability of 4000, current of 5A, and 1000 turns per meter) is calculated to be 12.56 mT, corresponding to option b in the question.

Step-by-step explanation:

The question concerns the calculation of the magnetic field inside a solenoid. Given the information: relative permeability μᵣ = 4000, current I = 5A, and number of turns per unit length (n) = 1000 turns/meter, the formula for the magnetic field B inside a solenoid is B = μᵣμ₀0nI, where μ₀0 is the vacuum permeability (μ₀0 ~ 4π × 10⁻⁷ T⋅m/A). Substituting the given values and the known value of μ₀0, we can calculate the magnetic field.

As the result is in the standard range for magnetic fields generated by typical solenoids, the estimated magnetic field strength would be in the order of milliteslas (mT), making option b. 12.56 mT the correct answer.