Resistance

• What does electricity involve in an electric circuit?

  A transfer of energy
• What type of energy does a cell contain?

  Chemical energy
• What is carried by the current in a circuit?

  Electrical energy
• What is the flow of electrons around the circuit called?

  Current
• What happens to electrical energy when electrons pass through a lamp?

  It is transferred to other forms of energy
• What is used to work out energy transfers in a circuit?

  Potential difference
• What is the potential difference of the cell mentioned?

  9 volts
• How much electrical energy does the current carry per coulomb of charge?

  9 joules
• What does a potential difference of 9 volts across the lamp indicate?

  All energy is transferred by the lamp
• What causes energy transfer in components?

  Resistance
• What does resistance tell us?

  The potential difference required to drive a current
• What happens when electrons collide with atoms in a metal?

  Electrical energy is transferred into other forms
• What is the unit for resistance?

  Ohm
• What is the equation for calculating resistance?

  Resistance = potential difference / current
• Why do many students prefer to use a triangle for equations?

  It helps visualize the relationship
• What is the resistance of lamp A with a current of 1 ampere and a potential difference of 1 volt?

  1 ohm
• What is the resistance of lamp B with a current of 1 ampere and a potential difference of 10 volts?

  10 ohms
• How do you calculate the potential difference needed for a certain current?

  Potential difference = current × resistance
• If the current is 0.5 amp and the resistance is 50 ohms, what is the potential difference?

  25 volts
• What is the relationship between potential difference, current, and resistance?

  • Potential difference (V) = Current (I) × Resistance (R)
  • Resistance (R) = Potential difference (V) / Current (I)
• What are the key concepts related to resistance in circuits?

  • Resistance indicates energy required to drive current
  • Measured in ohms
  • Higher resistance means more energy needed
• What are the steps to calculate resistance in a circuit?

  1. Identify potential difference (V) in volts
  2. Identify current (I) in amperes
  3. Use the formula: R = V / I
• What forms of energy can electrical energy be transferred into?

  • Light energy
  • Thermal energy
  • Mechanical energy