# Homework Help: Question about the properties of inductive circuits?

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1. Feb 13, 2015

### ah4p

I'm studying for my prelim and am trying to understand inductance better based on some questions I have done I've come up with these statements can anyone confirm they are true

the back emf in an inductive circuit at any given time equal to the voltage across the inductor
I initially thought you had to subtract the voltage across the inductor from the supply voltage to find back emf

the more turns in the coil of wire the greater the back emf and the smaller the maximum current

there was a question on how the increasing the number of turns will affect the time taken to reach the maximum current
My guess is that the increased number of turns will increase the induced back emf thus there is more resistance to current so it will take longer to reach its maximum
since back emf = -L dI/dt

also
if you remove the core from an inductor there will be no effect on maximum current but the inductance and back emf are both reduced so the time to reach max. current is smaller

thanks for any help :)

2. Feb 13, 2015

### Staff: Mentor

3. Feb 13, 2015

### Staff: Mentor

Thread re-opened. Please post questions like this in the HH, Intro Physics forum. The Advanced Physics HH forum is for upper-division and graduate level questions. Thanks. :-)

Also, please do not delete the HH Template that you are provided when starting new threads. Your post above is very confusing without the Template. It is hard to tell what the questions are, and what your answers are. Can you please be more clear about what are the questions and what are your proposed answers? Thanks.