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What causes electric field/ magnetic field?

  • Thread starter YMMMA
  • Start date
  • #1
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Homework Statement


What causes electric field? What causes magnetic field?
(I) stationary electric fields
(II) moving electric charges
(III) a changing magnetic field
IV) a current-carrying wire

Homework Equations


E=F/q
B=μI/2πr
E electric field
F elecric force
Q charge
B magnetic field
I current
r distanc(radius)

The Attempt at a Solution


[/B]
I) Stationary electric charges creates electric fields tht points radially outward/inward.
II) moving electric charges, like current flowing through a wire, cause magnetic fields. Can it produce electric fields as well since it is a charge?
III) That statement has me confused. It’s a change in magnetic field, so current is induced. It’s Faraday’s law. But what is caused exactly? Any hints?
IV) same as II
 

Answers and Replies

  • #2
DrClaude
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II) moving electric charges, like current flowing through a wire, cause magnetic fields. Can it produce electric fields as well since it is a charge?
Yes, the electric field is there whether the charge is moving or not.

III) That statement has me confused. It’s a change in magnetic field, so current is induced. It’s Faraday’s law. But what is caused exactly? Any hints?
A current can only be induced if there is a conductor. Faraday's law is one of the Maxwell equations, so you can check what they look like in free space.

IV) same as II
Review this question with respect to what I wrote for II.
 
  • #3
156
10
Then, a moving chrage causes both electric and magnetic fields.
I have check maxwells equations, and yes, it can create electric fields.
Current carrying wire creates only magnetic field. Am I right?
 
  • #4
DrClaude
Mentor
7,163
3,308
Then, a moving chrage causes both electric and magnetic fields.
I have check maxwells equations, and yes, it can create electric fields.
Current carrying wire creates only magnetic field. Am I right?
Yes, because the net charge is zero (the wire itself is neutral).
 

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