Electricity unit test

• Parallel circuits

  Allows lights to stay on if one goes out
• Series circuit


  Voltage is spread out across all loads
• Resistance


  The amount of difficulty electrons have as they flow through a material
• Difference between current in series vs parallel circuit

  In parallel, current is the same everywhere & in series it spreads out (splits)
• Units to measure resistance


  Ohms (Ω)
• Units to measure current

  Amperes (A)
• Parts of any circuit


  • Load
  • Energy/Power Source
  • Connectors
  • Switch
• Current measurement at ammeter

  • 5 Amps
• Resistance of electric motor is 10 Ω, current is 2 A

  Voltage of outlet must be 20 V
• Effect of more loads in a parallel circuit

  Decrease resistance
• Circuit powered by two 3 V cells, light bulb resistance 10.0 Ω

  Current flowing is 0.6 A
• Ohm's Law: if resistance increases

  Current will decrease (flow slower)
• If voltage increases


  Current will increase (flow faster)
• If a bulb is blown in a series circuit


  All other bulbs/loads go out
• Units to measure voltage

  Volts (V)
• What happens when a positive rod is brought near a neutral plastic ball

  Electrons in the ball are attracted to the positive rod and move to the side of the ball facing the rod
• Why Snuffles became positively charged

  Snuffles transferred electrons to the balloons which made him positively charged
• What a neutral object always contains


  The same number of protons and electrons
• What is not part of the Law of Electric Charges

  Neutral objects are attracted to both positive & negative objects
• A positive charge is created when an object loses electrons
• If you connect a negatively charged object to the ground, the extra electrons flow FROM the object INTO the Earth
• Objects with the same charges repel each other
• Rubbing wood and nylon

  Wood becomes positively charged, nylon becomes negatively charged
• Rubbing ebonite and human skin

  Ebonite becomes positively charged, human skin becomes negatively charged
• Rubbing rabbit and cat

  Rabbit becomes positively charged, cat becomes negatively charged
• Energy transformation in playing guitar

  Mechanical - sound
• Energy transformation in car's engine moving a car

  Electrical - Mechanical - Radiant - sound - thermal
• Energy transformation in watching TV/Video


  Electrical - Sound - Radiant
• The current is the flow of electrons through a circuit.
• Electric circuits are closed loops that allow electricity to flow from one point to another.
• A battery produces an electrical potential difference, which causes a flow of charge (current) when connected to a component or another cell.
• A conductor allows electricity to pass easily through it.
• Types of energy

  1. Electrical
  2. Mechanical
  3. Thermal (heat)
  4. Radiant (light)
  5. Sound
  6. Chemical
• Law of conservation of energy: Energy cannot be created or destroyed, it can only be transformed and transferred
• Static Electricity = ("Static" = Not moving) Charge that stays still until it moves suddenly to another object
• • Opposite charges attract
  • Same charges repel
  • Neutral charges attract both protons and electrons
  • Neural and neutral stay the same
• **Electrostatic series**

  If the object is higher on the list than it will become positively charged if it is lower on the list it will become negatively charged
• Current electricity:

  • An electric charge that flows -> moving

  *Cannot flow through insulators (i.e rubber) but can flow through conductors (i.e metal)
• Parts of a circuit:

  • Energy source (i.e. Battery)
  • Load (Turns electricity into the type of energy needed - Converts)
  • Connectors (mostly used as wires - Conductor)
  • Switch (can turn on and off)
• Charging Objects: 3 ways of Charging objects are:

  • Friction (Rubbing 2 objects together)
  • Induction (2 objects brought NEAR each other)
  • Contact (2 objects attached/touching each other)