Physics 2

• Coulomb’s Law is the force of attraction or repulsion acting along a straight line between two electric charges is directly proportional to the product of the charges and inversely to the square of the distance between them
• Electric charge – is the basic property of matter carried by some elementary particles that governs how the particles are affected by an electric or magnetic field
• Electric charge - can be positive type or negative type. It occurs in discrete natural units and is neither created nor destroyed.
• Law of Charges

  1. Like repels
  2. Unlike attracts
• Electric Field is an electric property associated with each point in space when charge is present in any form.

  • A vector quantity
• Q - electric charge, source of electric field, source charge
• q - electric field strength, test charge
• Formula for Electric Field Strength

  1. E = F/q
  2. E = kQ/r2
• k - 8.99 x 10^9 Nm^2/C^2
• The other name for Coulomb's law is Electrostatic force
• Coulomb's law formula:

  F = kq1q2/r^2
• Electric Circuit - conducting path that forms a closed loop which charges move, energy is carried from one place to another
• Open circuit is like an open circle because there is a break in the line of flow.
• Closed circuit is like a closed circle or a completed circle.
• Electric Current motion of charge from one region to another
• Electric current is the amount of charge that passes a given point in a given amount of time
• Electric current is the movement of electrons through a wire
• Formula of finding current:

  I = dQ/dt
• electric field in a conductor causes charges to flow.
• Drift Velocity - average velocity reached by charged particles, such as electrons, in a

  material due to an electric field.
• Voltage creates an electric field in a conductor, making charged particles drift and causing current flow
• a small net flow in one direction is the drift
• The electric field does work on moving charges which results in kinetic energy (KE)
• Conventional Current - flow of positive charges from the positive to the negative terminal. It behaves as if the positive charge carriers cause current flow.
• Electron Flow - movement of negative charges (electrons) opposite to the direction of the electric field.
• • Current Density current per unit cross-sectional area (Amp/m^2)
• Current density formula:

  J = I/A
• Voltage (V) - The amount of work required in moving one electric charge from one point to the other. It pushes or moves electrons in an electrical circuit  The SI unit of voltage is volt.
• Current - The amount of charge passing through the circuit in unit time. The SI unit Electric current is the ampere, or amp.
• Power (W) - The product of work done and the number of electrons passing through the circuit in unit time. Watt is the unit. The rate at which energy is transformed in an electrical circuit.
• Electricity - A form of energy produced by the movement of electrons
• Resistor - an electrical component that limits or regulates the flow of electrical current in an electronic circuit
• Resistance (R or Ω) The opposition offered by the flow of current in the circuit.
• electrical insulators like rubber tend to have very high resistance and low conductivity
• electrical conductors like metals have very low resistance and high conductivity
• Resistance is the capacity of an electrical material to regulate the flow of current.
• Resistance is anything that keeps the current from flowing
• Capacitor - a two-terminal electrical device that stores energy in the form of electric charges
• Uniform Electric Field - a field in which the value of the field strength remains the same at all points. If an electric field has the same magnitude and same direction everywhere
• Insulator - it holds  electrons within their atomic orbits or keeps instill electrons within the conductor.