# Flux funding question

1. Aug 29, 2009

### nabliat

here is the question and solution:
http://i31.tinypic.com/347ttlj.jpg

i was asked to find the flux of the system
i know that
$$\phi=LI$$

why they divide the result by the number of turns??

in the previous question
i was told in the inductor which has certain L and certain I find the flux
and i was doing IL to find the flux although every inductor has a number of turns
and its not been divided by the number of it turns
the number of turns is not given at all.

2. Aug 29, 2009

### kuruman

Your expression above is the total flux. In the solution, they calculate the flux through one turn. Therefore the total flux needs to be divided by the number of turns N to find the flux through one turn.

3. Aug 29, 2009

### nabliat

in the previous question
i was told in the inductor which has certain L and certain I find the flux
and i was doing IL to find the flux although every inductor has a number of turns
and its not been divided by the number of it turns
the number of turns is not given at all.

4. Aug 29, 2009

### kuruman

You are not explaining yourself very well. Can you write the statement of the problem that you were asked to solve? Is it exactly the one whose solution you posted? If it is, then you do know that the numbers of turns is N=300 and I explained to you why they divide by N.

5. Aug 29, 2009

### nabliat

in this problem
http://i25.tinypic.com/bjeff6.jpg

they havent told how many turns construct the inductor
the emf equals =-derivative of flux

and the flux has to be devided by the number of turns

but they didnt do it here at all

why??

6. Aug 29, 2009

### kuruman

This is confusing. Please stop posting solutions to different problems and post - not a jpg file - but a statement of the problem that you wish to be helped on typed in by yourself and following the template provided by PF.

7. Aug 29, 2009

### nabliat

i am confused about why in some questions i am given
inductor without his number of turns

while in the other i am not given the number of turns in the inductor

8. Aug 29, 2009

### kuruman

Different problems have different given quantities. Each problem must be solved individually. There is no solution that fits all problems. That is why I asked you, what specific problem are you having difficulty with?

9. Aug 29, 2009

ok thanks :)