Outline four factors which affect the inductance of a inductor?

1. Number of turns: The inductance of an inductor is directly proportional to the number of turns of wire in the coil. More turns result in a higher inductance.

2. Cross-sectional area: The cross-sectional area of the coil affects the inductance of an inductor. A larger cross-sectional area results in a higher inductance.

3. Core material: The material of the core inside the coil can affect the inductance of an inductor. Different core materials have different magnetic permeabilities, which can impact the inductance.

4. Coil length: The length of the coil also affects the inductance of an inductor. A longer coil will have a higher inductance compared to a shorter coil.