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Easy Java Simulations (2001- ) => electromagnetism => Topic started by: ahmedelshfie on April 12, 2010, 02:17:41 am



Title: A loop rotating in a magnetic field (How electric power generator works!
Post by: ahmedelshfie on April 12, 2010, 02:17:41 am
This applet created by Prof Hwang
Modified by my self
I add tow bars for (sc) and (time)
Original project:A loop rotating in a magnetic field (How electric power generator works!) (http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=915msg4942;topicseen#msg4942)


Title: Re: A loop rotating in a magnetic field (How electric power generator works!
Post by: ahmedelshfie on April 21, 2010, 02:42:23 am
When a loop rotating in a uniform magnetic field.
The magnetic flux is changing which will induce electric field along the loop (produce voltage).
If the loop is rotating with constant angular velocity \omega . (The angle is \omega t)
The magnetic flux in the loop will be $\Psi =\int \vec{B}\cdot d\vec{A}= B A cos(\omega t)$
So the induced emf $= -\frac {d\Psi}{dt}=B A \omega sin(\omega t)$

The following simulation show how it works dynamically.


Title: Re: A loop rotating in a magnetic field (How electric power generator works!
Post by: Fu-Kwun Hwang on April 21, 2010, 10:06:44 am
You need to add TeX equation between $ to be displayed as equation.
I have added dollar sign for the above posted message for you!


Title: Re: A loop rotating in a magnetic field (How electric power generator works!
Post by: ahmedelshfie on April 21, 2010, 12:21:11 pm
Yes prof,, i had the text information and equations from topic
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=912.0
So i think I'm make wrong right ???


Title: Re: A loop rotating in a magnetic field (How electric power generator works!
Post by: Fu-Kwun Hwang on April 21, 2010, 04:50:40 pm
You need to add dollar sign for those equations.
Otherwise, those equation would not be convert to image.

The following is what you have copied.
Code:
This simulation shows a current loop in uniform magnetic field.
The black arrows show the force due to magnetic field on the loop.
\vec{F}= q \vec{v} \times \vec{B} or \vec{F}= I \int d\vec{\ell} \times \vec{B}
The magnetic field in in the +Z direction if Bz>0.
Then ,torque for the loop is calculated from definition \vec{\tau}=\vec{r}\times\vec{F}

Because the current flow in the same counter-clockwise direction.
The force on the loop change sign during each helf cycle.
If we current reverse direction during each helf cycle, the following device can turn into a motor.
A voltage source is needed in the loop to drive the current.


Title: Re: A loop rotating in a magnetic field (How electric power generator works!
Post by: ahmedelshfie on April 21, 2010, 10:51:46 pm
I understand prof so when i would typing any equations i add $ between equations
For convert to picture right


Title: Re: A loop rotating in a magnetic field (How electric power generator works!
Post by: Fu-Kwun Hwang on April 22, 2010, 02:48:25 pm
Yes!  :D


Title: Re: A loop rotating in a magnetic field (How electric power generator works!
Post by: ahmedelshfie on April 22, 2010, 05:19:06 pm
Yes prof  :)