energy transferred in circuits

• What happens when charge passes through a resistor?

  Energy is transferred to heat, increasing temperature
• How does energy dissipate into the environment?

  Through thermal conduction, convection, and radiation
• What is an advantage of the heating effect of current?

  It is used in electric heaters
• What is a disadvantage of the heating effect of current?

  It can cause devices to overheat and fail
• What happens when electrical current does work against resistance?

  Electrical energy is dissipated as thermal energy
• What factors affect the amount of heat produced in a circuit?

  Current and resistance
• What occurs when resistance is reduced in a circuit?

  Current may increase
• How does the heating effect occur in metals?

  Through collisions between electrons and metal ions
• What appliances utilize the heating effect of current?

  Electric heaters, ovens, toasters, kettles
• Why is heat in electrical appliances often unwanted?

  It can be dangerous and reduce efficiency
• How can heat in wires be reduced?

  By reducing current or using lower resistance wires
• What is the unit of power?

  Watt (W)
• What does power measure in electrical devices?

  The rate of energy transfer per second
• How is energy transferred calculated in a circuit?

  Using the equation E = P × t
• What does the equation E = I × V × t represent?

  Energy transferred in joules
• How much energy is transferred when a current of 0.7 A passes through a potential difference of 4 V for 1 minute?

  168 J
• What is the relationship between power and energy?

  Power is energy transferred per second
• What is the formula for calculating electrical power?

  P = IV
• How do you calculate energy transferred using power and time?

  E = P × t
• What happens if an appliance is plugged into a mains supply with a higher voltage than stated?

  It could fuse or cause a fire
• What is the power rating of an appliance?

  The amount of energy it transfers per second
• How does a 1 kW iron compare to a 2 kW iron in terms of energy usage?

  Both use the same energy in different times
• What is the potential difference across a 48 W motor with a current of 4 A?

  12 V
• What is the power through a 20 Ω resistor with a current of 6 A?

  720 W
• What mnemonic helps remember the power equation?

  “Twinkle Twinkle Little Star”
• What are the main methods of energy dissipation in electrical components?

  • Thermal conduction
  • Convection
  • Radiation
• What are the advantages and disadvantages of the heating effect of current?

  Advantages:

  • Useful in heating appliances

  
  

  Disadvantages:

  • Causes energy loss
  • Can pose fire hazards
• What factors determine the energy transferred by an appliance?

  • Time the appliance is on
  • Power of the appliance
• How do different appliances transfer energy electrically?

  • From mains supply to thermal store
  • From batteries to kinetic store
• What information is typically found on an appliance's power rating label?

  • Required potential difference
  • Frequency of supply
  • Power rating in watts
• What is the significance of using copper in electrical wiring?

  • Low resistance
  • Cost-effective
• What is the relationship between power and time in energy transfer?

  • Power is energy transferred per unit time
• What is the formula triangle for power, energy, and time?

  • Power (P) = Energy (E) / Time (t)
  • Energy (E) = Power (P) × Time (t)