Electricity and circuits

• What are the three subatomic particles in an atom?

  Protons, neutrons, and electrons
• Where are protons located in an atom?

  In the nucleus
• What is the charge of a neutron?

  Neutral
• What is the mass of a proton compared to an electron?

  Much greater
• What is the function of electric circuit diagrams?

  To represent electrical components and connections
• What symbols represent common electrical components in circuit diagrams?

  • Cell: long and short parallel lines
  • Battery: multiple long and short lines
  • Switch: break in a line
  • Voltmeter: circle with "V"
  • Ammeter: circle with "A"
  • Resistor: zigzag line
  • Variable resistor: zigzag with an arrow
  • Lamp: circle with "X"
  • Motor: circle with "M"
  • Diode: triangle with a line
  • Thermistor: resistor symbol with temperature indication
  • LDR: resistor symbol with light indication
  • LED: circle with two arrows
• What is the difference between series and parallel circuits?

  Series circuits have one path; parallel has multiple
• How is a voltmeter connected in a circuit?

  In parallel with a component
• What does potential difference (voltage) represent?

  Energy transferred per unit charge
• What is the formula for energy transferred?

  E = Q × V
• What does an ammeter measure?

  Current in a component
• How is electric current defined?

  Rate of flow of charge
• What is the formula for charge?

  Q = I × t
• What happens when a closed circuit includes a source of potential difference?

  There will be a current in the circuit
• What is meant by current conservation at a junction?

  Current entering equals current leaving
• How does changing resistance affect current?

  Increased resistance decreases current
• What is the formula for potential difference?

  V = I × R
• What happens to net resistance in series circuits?

  Net resistance increases
• What happens to net resistance in parallel circuits?

  Net resistance decreases
• How do you calculate currents in series circuits?

  By using Ohm's law
• What is the purpose of constructing electrical circuits in experiments?

  To test and measure electrical relationships
• What is the relationship between potential difference, current, and resistance for a resistor and a filament lamp?

  • Resistor: Ohm's law applies (linear relationship)
  • Filament lamp: Non-linear relationship (increases with temperature)
• How does current vary with potential difference for a filament lamp?

  Current increases with potential difference
• How does current vary with potential difference for a diode?

  Current flows only in one direction
• How does current vary with potential difference for fixed resistors?

  Current is directly proportional to voltage
• How does the resistance of an LDR vary with light intensity?

  Resistance decreases with increased light intensity
• How does the resistance of a thermistor vary with temperature?

  Resistance decreases with increased temperature
• How can circuits be designed to explore resistance variation in devices?

  • Use filament lamps to observe heating effects
  • Use diodes to study current direction
  • Use thermistors to measure temperature changes
  • Use LDRs to measure light intensity effects
• What happens to energy when there is an electric current in a resistor?

  Energy is transferred as heat
• How is electrical energy dissipated in a resistor?

  As thermal energy in surroundings
• What causes energy transfer in a resistor?

  Collisions between electrons and ions
• How can unwanted energy transfer be reduced in wires?

  By using low resistance wires
• What are the advantages and disadvantages of the heating effect of electric current?

  Advantages:

  • Useful for heating appliances
  • Can be controlled for specific applications

  
  

  Disadvantages:

  • Can cause overheating and fires
  • Energy loss as heat in circuits
• What is the formula for energy transferred in terms of current, voltage, and time?

  E = I × V × t
• How is power defined in electrical terms?

  Energy transferred per second
• What is the formula for power in terms of energy and time?

  P = E ÷ t
• How is power transfer related to potential difference and current?

  Power is the product of voltage and current
• What is the formula for electrical power in terms of current and voltage?

  P = I × V
• What is the formula for electrical power in terms of current squared and resistance?

  P = I² × R
• How is energy transferred from batteries and mains to devices?

  Through electrical energy conversion