Electricity

• What is the AQA electricity topic primarily about?

  It is about electrical circuits and components.
• Why is it important to memorize circuit symbols?

  It allows us to draw circuits simply.
• What is the function of an ammeter in a circuit?

  To measure the current flowing through the circuit.
• How should an ammeter be connected in a circuit?

  It should be connected in series.
• What does a voltmeter measure?

  It measures the potential difference across a component.
• How should a voltmeter be connected in a circuit?

  It should be connected in parallel.
• What is electric current defined as?

  It is the rate of flow of electric charge.
• What is the equation for electric charge?

  Q = I \times T
• What does the symbol Q represent in the equation Q = I \times T?

  Q represents electric charge measured in coulombs.
• What does the symbol I represent in the equation Q = I \times T?

  I represents current measured in amps.
• What does the symbol T represent in the equation Q = I \times T?

  T represents time measured in seconds.
• How does electric current depend on potential difference and resistance?

  Current increases with higher potential difference and decreases with higher resistance.
• What is the equation relating potential difference, current, and resistance?

  V = I \times R
• If you know the potential difference and resistance, how can you find the current?

  Use the equation V = I \times R to solve for I.
• What characterizes an ohmic conductor?

  It has a constant resistance, resulting in a straight line graph of current versus potential difference.
• How does the resistance of a filament lamp change with temperature?

  Resistance increases as the filament lamp gets hotter.
• What is the function of a diode in a circuit?

  A diode allows current to flow in only one direction.
• What happens to the current through a diode when a negative potential difference is applied?

  The current is zero.
• How does a light dependent resistor (LDR) behave with changing light intensity?

  Resistance decreases as light intensity increases.
• What is a thermistor and how does it behave with temperature changes?

  A thermistor is a thermal resistor that decreases resistance as temperature increases.
• What are the main differences between series and parallel circuits?

  • Series Circuit:
  • Current is the same throughout (I1 = I2 = I3).
  • Potential difference is split (V1 = V2 + V3).
  • Total resistance increases with more resistors (R_total = R1 + R2).

  
  

  • Parallel Circuit:
  • Current splits at junctions (I1 = I2 + I3).
  • Potential difference is the same across each loop (V1 = V2 = V3).
  • Total resistance decreases with more resistors.
• What is the total resistance in a series circuit with resistors R1 and R2?

  R_total = R1 + R2.
• What happens to total resistance in a parallel circuit with multiple resistors?

  Total resistance decreases as more resistors are added.
• What is the equation for electrical power?

  P = V \times I
• How is energy transferred in a circuit related to power and time?

  Energy is equal to power times time (E = P \times t).
• What is the equation for energy transferred in terms of charge and potential difference?

  E = Q \times V
• What is the frequency of the UK mains electricity supply?

  50 cycles per second.
• What is the voltage of the UK mains electricity supply?

  230 volts.
• What are the three wires in a typical three-core cable?

  Brown (live), blue (neutral), and green/yellow (earth).
• What is the purpose of the earth wire in a three-core cable?

  To carry current safely to the ground in case of a fault.
• What is the National Grid?

  It is a system of cables and transformers linking power stations to consumers.
• How do transformers work in the National Grid?

  Transformers increase or decrease voltage to reduce energy losses.
• What happens when two insulators are rubbed together?

  Electrons are transferred, causing one to become negatively charged and the other positively charged.
• What is an electric field?

  An electric field is the region around a charged object where other charged objects experience a force.
• How do electric field lines behave around a positive charge?

  They point away from the positive charge.
• What happens to a positive charge placed in the electric field of another positive charge?

  It is repelled by the electric field.
• What are the key concepts covered in the AQA electricity topic?

  • Circuit components and symbols
  • Ohmic and non-ohmic conductors
  • Series and parallel circuits
  • Electrical power and energy equations
  • Direct current (DC) and alternating current (AC)
  • The National Grid and transformers
  • Static electricity and electric fields