Electricity Basics

Electricity

• Electric Charge:
  • Positive and negative charges
  • Like charges repel, opposite charges attract
  • Charge is measured in coulombs (C)
• Electric Current:
  • Flow of electrons from negative to positive terminal
  • Measured in amperes (A)
  • Ohm's Law: I = V/R (current = voltage / resistance)
• Electric Circuits:
  • Series circuits: components connected one after another
  • Parallel circuits: components connected between same points
  • Resistors, capacitors, and inductors are common circuit components

Magnetism

• Magnetic Fields:
  • Created by moving charges or changing electric fields
  • Measured in teslas (T)
  • Direction of magnetic field lines: right-hand rule
• Magnetic Forces:
  • Acting on moving charges or currents
  • F = qvB sin(θ) (force = charge * velocity * magnetic field * sine of angle)
• Electromagnets:
  • Coils of wire wrapped around a core, carrying current
  • Strength of magnetic field depends on number of turns, current, and core material

Waves

• Types of Waves:
  • Mechanical waves: require a medium (e.g., water, air)
  • Electromagnetic waves: no medium required (e.g., light, radio)
• Wave Characteristics:
  • Amplitude: maximum displacement from equilibrium
  • Frequency: number of oscillations per second (Hz)
  • Wavelength: distance between consecutive oscillations
  • Speed: wavelength * frequency
• Wave Interactions:
  • Reflection: wave bounces back
  • Refraction: wave changes direction
  • Diffraction: wave bends around obstacles

Thermodynamics

• Temperature:
  • Measure of average kinetic energy of particles
  • Measured in Kelvin (K) or Celsius (°C)
• Heat Transfer:
  • Conduction: direct contact between particles
  • Convection: transfer through fluid motion
  • Radiation: transfer through electromagnetic waves
• Laws of Thermodynamics:
  • Zeroth Law: thermal equilibrium
  • First Law: energy conservation (ΔE = Q - W)
  • Second Law: entropy increase (ΔS = ΔQ / T)

Mechanics

• Motion:
  • Displacement: change in position
  • Velocity: rate of change of displacement
  • Acceleration: rate of change of velocity
• Forces:
  • Gravity: attractive force between masses
  • Friction: resistive force between surfaces
  • Normal force: force exerted by a surface
• Energy and Work:
  • Kinetic energy: energy of motion
  • Potential energy: energy of position
  • Work: force * displacement (W = F * d)

Electricity

• Electric charge has two types: positive and negative, and like charges repel each other while opposite charges attract each other
• Electric charge is measured in coulombs (C)
• Electric current is the flow of electrons from the negative terminal to the positive terminal
• Electric current is measured in amperes (A) and calculated using Ohm's Law: I = V/R (current = voltage / resistance)
• Series circuits have components connected one after another, while parallel circuits have components connected between the same points
• Common circuit components include resistors, capacitors, and inductors

Magnetism

• Magnetic fields are created by moving charges or changing electric fields
• Magnetic fields are measured in teslas (T) and their direction can be determined using the right-hand rule
• Magnetic forces act on moving charges or currents and are calculated using F = qvB sin(θ) (force = charge * velocity * magnetic field * sine of angle)
• Electromagnets consist of coils of wire wrapped around a core, carrying current, and their strength depends on the number of turns, current, and core material

Waves

• There are two types of waves: mechanical waves (require a medium) and electromagnetic waves (no medium required)
• Wave characteristics include amplitude (maximum displacement from equilibrium), frequency (number of oscillations per second in Hz), wavelength (distance between consecutive oscillations), and speed (wavelength * frequency)
• Waves interact through reflection (bouncing back), refraction (changing direction), and diffraction (bending around obstacles)

Thermodynamics

• Temperature is a measure of the average kinetic energy of particles and is measured in Kelvin (K) or Celsius (°C)
• Heat transfer occurs through conduction (direct contact), convection (transfer through fluid motion), and radiation (transfer through electromagnetic waves)
• The Laws of Thermodynamics include the Zeroth Law (thermal equilibrium), the First Law (energy conservation: ΔE = Q - W), and the Second Law (entropy increase: ΔS = ΔQ / T)

Mechanics

• Motion involves displacement (change in position), velocity (rate of change of displacement), and acceleration (rate of change of velocity)
• Forces include gravity (attractive force between masses), friction (resistive force between surfaces), and normal force (force exerted by a surface)
• Energy and work involve kinetic energy (energy of motion), potential energy (energy of position), and work (force * displacement: W = F * d)