Theory behind investigating factors affecting inductance

[JohnayG]

Homework Statement

Hello,

I am currently doing an investigation to study the factors affecting inductance. The three variables i am using are the number of turns on the coil, the material of the core of the coil and putting 2 cores in series/parallel to see how this affects the inductance in a d.c circuit.

now i have done experiments for each whereby i measured V across inductor to allow me to work out I and therefore see the affect on L in L= -ε ÷(dI/dt)

i just have a couple of questions though. first of all, am i right in saying that my value for ε (self-induced emf) will the same as the supply voltage?

also, i am requesting some help with my theory work deriving the equation for each variable. i have done the theory for changing number of turns by showing how it affects the magnetic flux produced. but I am having problems with the other 2 variables i.e. changing the core/parallel & series circuits; where/what equation with should i start?

Any help hugely appreciated.
Thanks for your time.

 

[marcusl]

You don't say what kind of physics/engineering background you have. Have you seen the equations for series and parallel inductance, including mutual inductance? For iron-cored solenoids?

One immediate question: what is dI/dt in your equation, given that you are using DC?