Electricity

• What is the symbol for a wire in a circuit diagram?

  • A straight line
• What does an open switch symbol represent in a circuit?

  • A break in the circuit that prevents current flow
• What does a closed switch symbol indicate in a circuit?

  • A complete circuit allowing current to flow
• What is the symbol for a battery in a circuit diagram?

  • Two or more long and short parallel lines
• What does the symbol for a cell look like?

  • A single long and short parallel line
• What is the symbol for a voltmeter?

  • A circle with a "V" inside
• What does the symbol for an ammeter represent?

  • A circle with an "A" inside
• What is the symbol for a motor in a circuit diagram?

  • A circle with the letter "M" inside
• What does the lamp symbol look like in a circuit diagram?

  • A circle with a cross inside
• What is the symbol for a fuse?

  • A rectangle with a line through it
• What does the symbol for a resistor look like?

  • A zigzag line
• What is the symbol for a variable resistor?

  • A zigzag line with an arrow across it
• What does the symbol for an LDR resistor represent?

  • A rectangle with a line through it and a light symbol
• What is the symbol for a buzzer in a circuit diagram?

  • A circle with a "B" inside
• What does the symbol for a diode look like?

  • A triangle pointing to a line
• What is the symbol for a Light Emitting Diode (LED)?

  • A triangle pointing to a line with two arrows pointing away
• What is the equation for current flow?

  Q = I * t
• What does the current flow equation measured in?

  • Q is charge and it is measured in coulombs (C).
  • I is current and it is measured in amps (A).
  • t is time and it is measured in seconds (s).
• When current flows, electrical work is done and energy transferred.
• There are two types of current: direct and alternating. In a direct current, the flow of electrons is consistently in one direction around the circuit. In an alternating current, the direction of electron flow continually reverses.
• In an electric circuit, energy can be transferred from one place to another by moving electrons around.
• Electrons are negatively charged particles and they transfer energy through wires as electricity.
• Charge is a property of a body which experiences a force in an electric field. Charge is measured in coulombs (C).
• Current is measured using an ammeter. To measure the current through a component, the ammeter must be placed in series with that component.
• A current of 28A flows into a PC. What is the charge if this took 6 seconds?

  168 Coulombs (C)
• A current of 12A flows through a wire making a charge of 88C. What is the time taken? (Round to 3 significant figures)

  7.33 seconds
• 59C of Charge is made in 6 seconds. What is the current? (Round to 3 significant figures)

  9.83 Amps (A)
• What does a resistor do?

  Limits the electric current that flows through a circuit.
• Resistance is measured in ohms (Ω).
• What is the equation for potential difference (1 letter not words)

  V = I * R
• What does the equation for potential difference show?

  Potential Difference = Current * Resistance

  Where Potential Difference is measured in Volts (V), Current is measured in Amps (A), and Resistance is measured in Ohms (Ω)
• Current is measured in amps (A).
• What will the potential difference be if we have a current of 16A and a resistance of 2.2Ω?

  35.2 V
• What will the Current be if we have a Potential Difference of 66V and a Resistance of 4kΩ? (Round to 3sf)

  1kΩ = 1000Ω

  0.02 A
• What will the resistance be if we have a Potential difference of 2MV and a current of 6kA? (Round to 1 decimal place.)

  1MV = 10^6 V

  1kA = 1000 A

  333 Ω
• What will be the time taken to a electrical circuit with a Charge of 2.4x10^9 C, a Potential Difference of 4.8x10^6 V and a resistance of 0.012kΩ?

  1kΩ=1000Ω

  Current = 400000 A

  Time taken = 6000 Seconds
• The unit for charge is coulombs (C).
• What causes zero error in this experiment?

  Contact resistance and clip positioning
• What is a variable resistor used for?

  To control resistance in a circuit
• What causes zero error in this practical?

  Contact resistance and clip positioning