Electric Field: Deriving Equations and Understanding Charge Density

In summary, the conversation revolved around the topic of understanding the electric field of various shapes such as a line of charge, a ring, a semicircle, a line of charge at a point that bisects the line of charge, and a uniform disc. The individual needed help deriving the equations and understanding the role of charge density. They also requested a resource for finding information on the electric field of a semicircle.
  • #1
musicfairy
101
0
I need help with the electric field of a line of charge, a ring, semicircle, a line of charge at a point that bisects the line of charge, and a uniform disc. The teacher showed us how to derive those equations but he does it so fast that I didn't have time to copy them down. Even if I did I won't understand why he made certain moves. So can someone please show me how to derive the equations for the electric field and how everything works? I also don't understand the role charge density plays. In each one it comes up.
 
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  • #3
Thanks. That will go on my favorites list. But it doesn't have a semi circle. Any ideas where I can find that?
 
  • #4
I think the examples there should suggest ways to calculate it.
 

FAQ: Electric Field: Deriving Equations and Understanding Charge Density

What is an electric field?

An electric field is a physical field that surrounds a charged particle and exerts a force on other charged particles. It is a fundamental concept in electromagnetism and is represented by a vector that indicates the direction and strength of the force on a positive test charge placed in the field.

How is the electric field strength calculated?

The electric field strength is calculated by dividing the force exerted on a test charge by the magnitude of the charge. This can be expressed mathematically as E = F/q, where E is the electric field strength, F is the force, and q is the charge.

What is the relationship between electric field and charge density?

The electric field is directly proportional to the charge density. This means that as the charge density increases, the electric field strength also increases. Additionally, the electric field lines are closer together when the charge density is higher, indicating a stronger field.

How is the electric field equation derived?

The electric field equation is derived from Coulomb's law, which states that the force between two charged particles is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. By rearranging this equation, we can derive the electric field equation as E = kq/r^2, where k is the Coulomb constant, q is the charge of the particle creating the field, and r is the distance from the particle.

Can the electric field and charge density be negative?

Yes, the electric field and charge density can be negative. This indicates that the direction of the field or the sign of the charge is opposite to what is typically considered positive. Negative charge density is often seen in the presence of electrons, which have a negative charge, while positive charge density is seen with protons, which have a positive charge.

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