electricty

• What must be true for electrical charge to flow?

  The circuit must be closed
• What is required for charge to flow in a circuit?

  There must be a source of potential difference
• What does electrical current represent?

  Flow of electrical charge
• How does the rate of flow of charge relate to current?

  Greater flow rate means greater current
• What is the formula relating charge, current, and time?

  $Q =$$I \cdot t$
• What is true about current in a single closed loop?

  The current has the same value at any point
• What factors affect the current through a component?

  Resistance and potential difference
• How does resistance affect current for a given potential difference?

  Greater resistance results in smaller current
• What is the formula for potential difference, current, and resistance?

  $V =$$I \cdot R$
• What characterizes an ohmic conductor?

  Resistance is constant, current is proportional to potential difference
• What happens to the resistance of a filament lamp as temperature increases?

  The resistance increases with temperature
• How does a diode behave in terms of current flow?

  Current flows in one direction only
• What happens to resistance as current increases in a resistor?

  Resistance increases, current decreases
• How does temperature affect the resistance of a thermistor?

  Resistance is lower at higher temperatures
• How does the length of a wire affect its resistance?

  Greater length results in more resistance
• What is the behavior of an LDR in light conditions?

  Resistance decreases with greater light intensity
• What happens to a diode's resistance in the reverse direction?

  It has a very high resistance
• What characterizes a series circuit?

  Current follows a single path
• What is true about current in a series circuit?

  The current is the same everywhere
• How is total resistance calculated in a series circuit?

  Total resistance is the sum of resistances
• What characterizes a parallel circuit?

  Current splits into multiple paths
• What is true about potential difference in a parallel circuit?

  The potential difference is the same across each branch
• How is total current calculated at a junction in a parallel circuit?

  Total current is the sum of currents in branches
• What happens to total resistance when resistors are in parallel?

  Total resistance is less than the smallest resistor
• How do electric fields behave around charges?

  They point away from positive charges, towards negative charges
• What happens to the strength of an electric field with distance from the charge?

  Closer to the charge, the stronger the force felt
• What type of electricity supply is mains electricity?

  AC supply
• What is the frequency of domestic electricity supply in the UK?

  50 Hz
• What is the voltage of the domestic electricity supply in the UK?

  About 230 V
• How does AC current behave?

  It continuously varies from positive to negative
• What is the difference between AC and DC?

  AC changes direction, DC flows one way
• What color is the live wire in a plug?

  Brown
• What is the voltage of the live wire?

  230 V
• What is the purpose of the neutral wire?

  Completes the circuit
• What is the function of the earth wire?

  Prevents appliances from becoming live
• What happens if the live wire touches the metal casing?

  The casing becomes live, causing electric shock
• What is power in terms of energy transfer?

  Energy transferred per second
• How is power related to current and voltage?

  Power is directly proportional to current and voltage
• What is the formula for energy transferred in terms of power?

  $E =$$P \cdot t$
• What is the formula for energy transferred in terms of charge?

  $E =$$Q \cdot V$