Topic 2 - Electricity

• What is a filament lamp similar to?

  A light bulb
• What does a variable resistor look like?

  It has an arrow through it
• What does a fuse do in a circuit?

  Protects the circuit from overload
• What is the definition of current?

  Flow of electric charge
• What is the equation for charge?

  Q = It
• What are the units for charge, current, and time?

  Coulombs, Amperes, Seconds
• What drives electrons through a circuit?

  Potential difference or voltage
• What does resistance mean in a circuit?

  Electrons funnel through a smaller space
• What is Ohm's Law?

  V = IR
• What are the units for voltage, current, and resistance?

  Volts, Amps, Ohms
• How does the length and diameter of a wire affect resistance?

  Longer, thinner wires increase resistance
• What is a light-dependent resistor (LDR)?

  A resistor that depends on light
• How does temperature affect a thermistor's resistance?

  Higher temperature lowers resistance
• What happens to resistance as light intensity increases in an LDR?

  Resistance decreases
• What are the key differences between series and parallel circuits?

  **Series Circuit:**

  • Single loop with all components
  • Total potential difference is the sum
  • Current is the same everywhere
  • Total resistance is the sum of resistances

  
  

  **Parallel Circuit:**

  • Split circuit with multiple paths
  • Potential difference is the same everywhere
  • Total current is the sum of currents
  • Total resistance is less than the smallest resistor
• What is the effect of adding more resistors in series?

  Total resistance increases
• What happens to current at junctions in a parallel circuit?

  Current splits based on resistance
• What is the role of the live wire in a plug?

  Carries the current to the appliance
• What color is the earth wire in a plug?

  Green and yellow
• What is the equation for power in an electrical circuit?

  P = IV
• What does a step-up transformer do?

  Increases voltage in the wires
• Why is high voltage used in the National Grid?

  To reduce current and energy loss
• What does a step-down transformer do?

  Reduces voltage to a safer level
• What are the processes involved in the National Grid?

  1. Step-up transformer increases voltage
  2. Electricity travels long distances
  3. Step-down transformer reduces voltage for safety
  4. Electricity delivered to homes
• What is electricity defined as?

  The flow of charge or charges
• What do electrons carry in a circuit?

  Energy from a source to a component
• What is the symbol for a cell?

  A single long line and a short line
• What is a battery?

  Several cells connected in line
• What is required for charges to flow in a circuit?

  Complete loops of components and wires
• What happens to the energy of electrons as they pass through a bulb?

  It is converted into light and heat
• What is the term for the movement of charge?

  Current
• From which terminal do electrons flow in a circuit?

  From the positive terminal to the negative
• What does potential difference (PD) indicate?

  Energy transferred per coulomb of electrons
• What does a 1-volt battery supply?

  One joule per coulomb of electrons
• How is PD measured?

  With a voltmeter connected in parallel
• What happens to the voltage across a bulb in a circuit?

  It remains the same as the battery voltage
• What is the equation for potential difference (PD)?

  PD = energy / charge
• What is the symbol for charge?

  Q
• What does current measure?

  The rate of flow of charges
• What is the equation for current?

  I = Q / T