GENPHY2-ELECTRIC-FIELD-1-1

ELECTROSTATICS AND COULOMB'S LAW

• General Physics 2 Overview

Electric Field Lines

• Field Maps of different Charge Distributions

  • Visual representation of electric fields around charges.

• Properties of Electric Field Lines

  • Start on positive charges and end on negative charges.

  • Never intersect.

  • Closer lines represent stronger fields.

Electric Field

• Electric Force

  • Non-contact force exerted by charged objects.

  • Creates an electric field in the surrounding space.

• Electric Field of a Point Charge

  • Defined as the force exerted on a tiny test charge divided by the magnitude of that charge.

  • Formula: ( E = \frac{F}{q} )

    • Where:

      • ( E ) is electric field (N/C)

      • ( F ) is force (N)

      • ( q ) is test charge (C)

• Principle of Superposition

  • Total electric field from multiple charges is the vector sum of the individual fields.

Historical Context

• Newton's Law of Universal Gravitation

  • Concept of force at a distance was controversial.

• Michael Faraday

  • Developed the concept of field lines, representing forces in an electric field.

Characteristics of Electric Field Lines

Negative Point Charge

1. Lines are radially inward.

2. Perpendicular to the surface of the charge.

3. Stronger field magnitudes indicated by the density of lines.

Positive Point Charge

1. Lines are radially outward.

2. Orientation remains perpendicular to the surface.

3. Again, strength is indicated by line density.

Electric Dipole

1. A pair of equal but opposite charges.

2. Lines directed from positive to negative charges.

Two Parallel Metal Plates

• Electric field lines between oppositely charged plates are parallel and equally spaced.

• Field is uniform between the plates, indicating consistent magnitude.

Properties of Electric Field Lines Summary

1. Origin on positive charges, end on negative charges.

2. Never intersect.

3. Texture density indicates field strength.

4. Number of lines proportional to charge magnitude.

Electric Field as a Vector Quantity

• Electric field (E) represented mathematically calculates the force on a test charge by dividing the force by the charge itself.

Sample Problems

Electric Field of a Single Point Charge

• Problem solving steps outlined for calculating electric fields at specific distances from point charges.

Electric Field Between Two Charges

• Example highlights calculating direction and magnitude of the electric field at a given point between two charges.

  • Forces acting on a test charge placed in an electric field.

Electric Field Above Two Point Charges

• Steps to identify individual electric fields from two point charges and calculating the resultant field using vector addition.

Assignment Examples

1. Calculate electric field strength due to a point charge at a certain distance.

2. Determine forces acting on a test charge in the vicinity of dipoles and point charges.