A long solenoid with 20 turns per centimeter has a core of iron-silicon. When the current is 1.50 A, the magnetic field inside the core is 4.50 T. The applied field _app is approximately A) 1.88 mT B) 3.77 mT C) 4.32 mT D) 3.87 mT E) 1.93 mT

Question

Quizplus · Accepted Answer

The magnetic field inside a solenoid is given by:
B = μ n I
where μ is the permeability of the core material, n is the number of turns per unit length, and I is the current through the solenoid.

We can rearrange this equation to find the applied field:
B_app = B / (μ n)
The permeability of iron-silicon is approximately 5000 µT/mA, or 5 µT/A.cm.

Substituting the given values, we get:
B_app = 4.50 T / (5 µT/A.cm * 20 turns/cm * 1.50 A)
B_app = 3.77 mT

Therefore, the best choice is B.

A Long Solenoid with 20 Turns Per Centimeter Has a Core