Question

Which changes will cause an increase in the magnetic field of a solenoid? Check all that apply.

using more wire loops
using fewer wire loops
using a larger current
using a smaller current
increasing the spacing between loops
decreasing the spacing between loops

Answer 1

The magnetic field of an ideal long solenoid is B = μ0 n I, where n = (turns per unit length) and I is the current. So B increases when n or I increases.

Check all that apply:
- using more wire loops — Yes (increases n)
- using fewer wire loops — No (decreases n)
- using a larger current — Yes (increases I)
- using a smaller current — No (decreases I)
- increasing the spacing between loops — No (reduces n)
- decreasing the spacing between loops — Yes (increases n)

(Assumes the solenoid length and core material remain the same.)