# What is the difference b/w a magnetic field and electric field?

Discussion in 'MCAT Study Question Q&A' started by spo01, May 11, 2008.

1. ### spo01MemberBronze DonorClassifieds Approved 10+ Year Member

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May 1, 2006
Miami Shores
i just can't grasp the difference. i know a change in one creates the other, but i don't really understand what this means either.

3. ### craniotomy30 2+ Year Member

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Aug 25, 2007
An electric field is set up by any type of non-neutral charge. Also, the force of a electric field is parallel to the displacement of a point charge. A magnetic field is set up by a moving, non-neutral charge, like a current. The force of a magnetic field is perpendicular to velocity of the affected particle.

4. ### BlackSails 2+ Year Member

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Apr 4, 2007
Constant magnetic fields also do no work.

5. ### NeuroChaos 2+ Year Member

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Mar 26, 2008
An electric field causes electron (or protons) to move. It exerts a force upon those particles. So the particues move in one direction or another. Now, you know that movement of charges is also known as current. Thus electric field causes current.
This current creates a magnetic field. We know that current creates a magnetic field from the biot savert law and ampers law.
That is why when you change one the other is created. When you change E field, current is created and this current creates B field. When you change B field, you are effecting the current in some way becuase changing a current is the only way to change B field. If you are changing current, than E field is changing.
Did get you totally confused? It is kind of confusing.

6. ### spo01MemberBronze DonorClassifieds Approved 10+ Year Member

527
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May 1, 2006
Miami Shores
thanks guys
i am getting the main points (which i think is probably good enough for the mcat): when to use the RHR, when work is created, etc. it's just visualizing it is the hardest. i've tried you-tube'ing it, googling for images, and am yet to find a good comparsion.

7. ### Character 5+ Year Member

Apr 23, 2008
all you need to know is that magnetic fields dont exist unless charges are moving. Electric fields exist even when charges are still.....and magnetic fields dont cause a change in velocity but causes uniformed circular motion..you should be fine with that.

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Oct 17, 2007
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Moving to Study Q&A

9. ### SKation

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Jan 15, 2014
Hey,

Does a constant electric field create a magnetic field? This is the only aspect im confused on cause a still charge doesnt.

Thanks!