Science energy revision term 2

    Cards (32)

    • What is power defined as in physics?
      Power is the amount of energy transferred each second.
    • In which unit is power measured?
      Power is measured in watts (W).
    • What does a power rating of 100 watts indicate about a device?
      It means that 100 joules of energy are transferred each second.
    • What is the relationship between kilowatts and watts?
      1 kilowatt = 1000 watts.
    • How can you calculate the energy transferred by an appliance using its power rating?
      • Use the formula:
      Energy transferred (J) = Power (W) × Time (s)
    • What is the formula to calculate energy transferred in joules?
      Energy transferred in joules (J) = Power in watts (W) × Time in seconds (s).
    • Why might some appliances have their power rating shown in kilowatts instead of watts?
      Because they transfer large amounts of energy.
    • How does the power rating of an appliance affect the energy transferred over time?
      A higher power rating results in more energy transferred in the same amount of time.
    • What is work defined as in physics?
      Work is done when a force causes an object to move.
    • How is work related to energy in physics?
      Work is a measure of the energy transferred when a force acts over a distance.
    • In what situations is work done besides moving an object?
      Work is done when a force compresses or extends a spring or other flexible object.
    • What is the relationship between energy transferred and work?
      • Energy transferred = Work
      • Both are measured in joules (J)
    • What unit is used to measure work and energy?
      Joules (J)
    • What does it mean when work is done on a flexible object?
      It means that a force is either compressing or extending the object.
    • What is the formula for work done in joules (J)?
      Work done (J) = force (N) x distance (m)
    • What is conduction?
      Conduction is the flow of heat energy from high to low temperature without overall movement of material.
    • Which materials are considered good conductors of heat energy?
      Metals are good conductors of heat energy.
    • What are poor conductors of heat called?
      Poor conductors of heat are called insulators.
    • How are atoms in a solid held together?
      The atoms of a solid are held together by chemical bonds.
    • What happens to atoms in a solid when they absorb heat energy?
      They vibrate faster and with bigger amplitude.
    • How does heat energy transfer in solids?
      Heat energy transfers from atom to atom through vibrations.
    • Why is conduction in metals faster than in non-metals?
      Conduction in metals is faster due to free electrons and collisions with metal ions.
    • What are free electrons in metals responsible for?
      Free electrons in metals are responsible for good thermal conductivity.
    • What is convection?
      Convection is the flow of heat energy by movement of a fluid from high to low temperature.
    • What types of materials are considered fluids?
      Liquids and gases are considered fluids.
    • How does convection occur in fluids?
      Convection occurs when particles with high heat energy move and replace particles with less heat energy.
    • Why is water heated from the bottom in kettles and saucepans?
      Water is heated from the bottom to easily set up convection currents.
    • What happens in a lava lamp during convection?
      The wax warms up, expands, becomes less dense, and rises, creating convection currents.
    • What are the processes involved in conduction in metals?
      • Collisions between fast-moving free electrons and metal ions
      • Passing vibrations from atom to atom
    • What are the characteristics of good insulators?
      • Poor conductors of heat
      • Traps air (e.g., trapped air, hair, fur, feathers, wool)
    • What is the difference between conduction in metals and insulators?
      • Metals: conduction by free electrons and vibrations
      • Insulators: conduction only by passing vibrations
    • How does heat transfer occur in a beaker heated by a Bunsen flame?
      1. Heat is transferred by conduction through the glass.
      2. Water near the flame heats up.
      3. Convection currents are set up in the water.