Current, Potential difference and Resistance

• What is the symbol for a light-emitting diode?

  LED
• What does a resistor do in a circuit?

  Sets the current in a circuit
• What is the function of a battery?

  Provides electrical energy in a circuit
• What does a lamp do in a circuit?

  Emits light when current passes through
• What is the purpose of an ammeter?

  Measures current in amps
• What does a voltmeter measure?

  Measures potential difference in volts
• What happens to a fuse if the current is too large?

  Melts and breaks the circuit
• What does a diode do?

  Allows current to flow in one direction only
• What is a thermistor used for?

  Sensor in heating systems
• What does an LDR do?

  Controls streetlights based on light
• What is the function of an LED?

  Emits light when current passes through
• What are the rules for drawing a circuit diagram?

  • Use a pencil and a ruler
  • Leads must be straight lines
• What is the difference between a series circuit and a parallel circuit?

  • Series Circuit: One route, current flows through all components
  • Parallel Circuit: Multiple routes, current does not flow through all components
• What is electric current?

  A flow of electrical charge
• What must a closed circuit include for electrical charge to flow?

  A source of potential difference
• What is the equation to calculate charge?

  Charge = Current x Time
• How much charge flows with a current of 60 amps for 30 seconds?

  1800 C
• Calculate the charge through a resistor with a current of 89 amps for 43 seconds.

  3827 C
• What are the units for charge, current, and time?

  • Charge: Coulombs (C)
  • Current: Amperes (A)
  • Time: Seconds (s)
• What is the relationship between charge flow, current, and time?

  Charge flow = Current x Time
• What happens to current in a closed loop circuit?

  It has the same value at any point
• What is resistance measured in?

  Ohms (Ω)
• How does resistance affect current flow?

  High resistance slows down current flow
• What is the relationship between resistance and current?

  • High resistance = Low current
  • Low resistance = High current
• What is the equation for potential difference?

  V = I x R
• What do electrons flow towards in a circuit?

  Towards the positive terminal
• What is the effect of high resistance on electron flow?

  Slows down the flow of electrons
• What is the effect of low resistance on electron flow?

  Does not stop the flow of electrons
• What is the charge flow through a resistor with a current of 0.020 A for 180 seconds?

  1. 6 C