Jump to content


Welcome to BrainDen.com - Brain Teasers Forum

Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account.
As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends.

Of course, you can also enjoy our collection of amazing optical illusions and cool math games.

If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top.
If you have a website, we would appreciate a little link to BrainDen.

Thanks and enjoy the Den :-)
Guest Message by DevFuse
 

Photo
- - - - -


  • Please log in to reply
4 replies to this topic

#1 Ventum

Ventum

    Junior Member

  • Members
  • PipPip
  • 47 posts

Posted 18 March 2009 - 12:23 AM

If people can list algebra based inductance equations for this I would be grateful.
Specifically I need to know the equation for inductance in a solenoid and loop.
Also an brief explanation of Right hand rule in a solenoid.
Hey, its worth a shot.
  • 0

#2 rookie1ja

rookie1ja

    Senior Member

  • Site Admin
  • PipPipPipPip
  • 1337 posts
  • Gender:Male
  • Location:Slovakia

Posted 18 March 2009 - 12:43 AM

see and act as per point 3 of this forum's rules

3. Show how far you've gotten with your problem and what it is you're stuck on.


  • 0

rookie1ja (site admin)
Optical Illusions
Support BrainDen

"To start: Press any key... Where's the 'any' key?" - Homer Simpson


#3 Ventum

Ventum

    Junior Member

  • Members
  • PipPip
  • 47 posts

Posted 18 March 2009 - 01:10 AM

Very well, @=theta
the formula has something to do with @
but the one for solenoid is uh uh ???
i know the right hand rules for most things just fuzzy on solenoids.
my point in the wording of the question was to prove that i understand most things, need help on certain parts.
for ex.
If the solenoid with diameter 15.5cm has 505 loops and it takes 2.77ms to spin from perpendicular with a mag field to parallel, with a V=.166 how strong is mag field?
i don't know what to do with the 505?
i wont round out everything because of decimals
i have .166=((?)/.00277)*((.0775^2)*(pi))

.166/((.0775^2)*(pi))=((?)/.00277)
(.00277)*(.166/((.0775^2)*(pi)))=?
but the answer i get for ? is incorrect

i am assuming the number of loops matter but i would like a general equation for solenoid and straight wire/circuit i have been working w/o a general equation for a while.
  • 0

#4 Yoruichi-san

Yoruichi-san

    "That Woman"

  • Members
  • PipPipPipPip
  • 3307 posts
  • Gender:Not Telling
  • Location:Outside the box

Posted 18 March 2009 - 02:33 AM

I assume this is okay since your HW doesn't require you to derive the expression:


For an uniformly wound solenoid having N turns and length l, that satisfies l>>r (radius of the windings), and assuming the core of the solenoid is filled with air, B is magnetic field, u0 is the permittivity of free space, @ is the magnetic flux, I is the current, A is the cross-sectional area:

For a closely spaced coil, the induced electromagnetic field (emf), according to Faraday's Law is related to the negative time rate of change of magnetic flux, which should be proportional to the source current in the circuit. The proportionality constant, L, is the inductance.

Induced emf=-Nd@/dt =-LdI/dt

-> L=N@/I

The magnetic field in a solenoid is: B=u0NI/l

-> @=BA=u0NAI/l

-> L=N@/I=u0N2AI/l



The right-hand rule tells you which direction the induced magnetic field will be pointing. If you point your thumb in the direction of the current then your fingers curve around in the direction of the induced magnetic field.
  • 0

Women are definitely stronger. We are [Fe]males, after all...

Some of what makes me me is real, some of what makes me me is imaginary...I guess I'm just complex. ;P

<3 BBC's Sherlock, the series and the man. "Smart is the new sexy."

Chromatic Witch links now on my 'About Me' page!  Episode 3 is finally here!

When life hands me lemons, I make invisible ink.


#5 Ventum

Ventum

    Junior Member

  • Members
  • PipPip
  • 47 posts

Posted 18 March 2009 - 04:03 AM

Thanks so in the above problem i would multiply my final expression by 505? and the right hand makes sense thank you.
  • 0




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users