Thermal Energy Transfers Quiz
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Questions and Answers

What is thermal energy primarily a measure of?

  • The total amount of energy in a substance
  • The potential energy of object positions
  • The average kinetic energy of particles (correct)
  • The energy lost during phase changes

    • Which temperature represents Absolute zero?

  • 100°C
  • 0°C
  • -273°C (correct)
  • 273°C

    • Which method of thermal energy transfer occurs mainly in solids?

  • Radiation
  • Evaporation
  • Convection
  • Conduction (correct)

    • What role do free electrons in metals play during conduction?

    <p>They facilitate the transfer of kinetic energy.</p> Signup and view all the answers

    Why do gases and liquids generally have low thermal conductivity?

    <p>Particles are too far apart in gases and slide past each other in liquids.</p> Signup and view all the answers

    What happens to particles in a substance as it is heated?

    <p>They gain kinetic energy and vibrate more.</p> Signup and view all the answers

    What is a primary reason thermal conduction is less effective in liquids and gases compared to solids?

    <p>Particles are more dispersed and can’t collide effectively.</p> Signup and view all the answers

    What occurs during a chain reaction of thermal energy transfer?

    <p>Energy is transferred from hot parts to cooler parts repeatedly.</p> Signup and view all the answers

    What primarily causes the expansion of fluid when heated?

    <p>The particles move faster and take up more volume.</p> Signup and view all the answers

    What happens to hot liquid or gas when it is warmed?

    <p>It rises into cooler areas.</p> Signup and view all the answers

    Which variable needs to be controlled to ensure an accurate investigation of convection?

    <p>Mass of the potassium permanganate crystal.</p> Signup and view all the answers

    Why does convection occur more effectively in gases than in liquids?

    <p>Gases have more kinetic energy.</p> Signup and view all the answers

    Which condition is NOT necessary for optimal convection?

    <p>Heat should be applied from above the liquid.</p> Signup and view all the answers

    What process primarily transfers energy from the Bunsen flame to the water in the beaker?

    <p>Conduction.</p> Signup and view all the answers

    In the context of the convection current, what happens to the hot fluid once it rises?

    <p>It cools and increases in density.</p> Signup and view all the answers

    What describes the motion created by hot fluid rising and cold fluid sinking?

    <p>Convection current.</p> Signup and view all the answers

    What is the primary method of heat transfer from the flame to the metal pan?

    <p>Radiation</p> Signup and view all the answers

    How does heat transfer from the water to the inside of a potato?

    <p>By conduction</p> Signup and view all the answers

    What occurs at thermal equilibrium in an object?

    <p>It absorbs and emits heat at the same rate.</p> Signup and view all the answers

    Which heat transfer process primarily occurs through the metal pan?

    <p>Conduction</p> Signup and view all the answers

    Which surface is the best absorber and emitter of infrared radiation?

    <p>Matt black</p> Signup and view all the answers

    What happens to a dark object placed next to a heat source compared to a light object?

    <p>The dark object heats up faster than the light one.</p> Signup and view all the answers

    What role does a vacuum flask play in energy transfer?

    <p>It reduces heat transfer by conduction, convection, and radiation.</p> Signup and view all the answers

    Which of the following correctly describes a convection current?

    <p>Hot particles gain kinetic energy and rise.</p> Signup and view all the answers

    Which surface is the poorest reflector of infrared radiation?

    <p>Shiny white/silver</p> Signup and view all the answers

    What is an effective method of improving energy efficiency in a thermos flask?

    <p>Using an insulating cap</p> Signup and view all the answers

    Which type of surface is ideal for maximizing energy transfer on cooking pans?

    <p>Matt black</p> Signup and view all the answers

    What is the effect of surface area on the emission of infrared radiation?

    <p>Larger surface areas emit more infrared radiation.</p> Signup and view all the answers

    How is heat transferred through water?

    <p>Through convection primarily</p> Signup and view all the answers

    Which surface texture would be most effective for reducing unwanted energy transfer?

    <p>Shiny black</p> Signup and view all the answers

    Which combination of color and texture would provide the worst performance as an absorber and emitter?

    <p>Shiny white/silver</p> Signup and view all the answers

    What occurs to the thermal energy stores of ice cream and its surroundings?

    <p>The ice cream absorbs thermal energy from the surroundings.</p> Signup and view all the answers

    What is the primary role of the vacuum between the inner and outer walls of a vacuum flask?

    <p>It prevents heat loss by conduction and convection.</p> Signup and view all the answers

    How do the silvered glass walls of a vacuum flask contribute to insulation?

    <p>They reduce heat transfer by reflection of infrared radiation.</p> Signup and view all the answers

    What function does the outer wall of a vacuum flask serve?

    <p>It minimizes heat transfer by conduction to the external environment.</p> Signup and view all the answers

    What role does the insulated support of a vacuum flask play in heat retention?

    <p>It prevents heat transfer through the base.</p> Signup and view all the answers

    What type of insulation does cavity wall insulation provide in modern houses?

    <p>Reduction of heat loss via conduction through air spaces.</p> Signup and view all the answers

    Which characteristic of the inner wall of a vacuum flask helps minimize heat transfer?

    <p>Its reflective coating combined with smooth surface.</p> Signup and view all the answers

    What is the primary function of the outer case of a vacuum flask?

    <p>To shield the flask from physical damage and reduce heat loss.</p> Signup and view all the answers

    What is a significant drawback of cavity walls without insulation?

    <p>They create significant convection currents through air spaces.</p> Signup and view all the answers

    What material can be placed behind radiators to enhance thermal radiation reflection?

    <p>Shiny and reflective material</p> Signup and view all the answers

    Which type of window frame is least efficient in preventing heat loss?

    <p>Steel frames</p> Signup and view all the answers

    What is the primary reason for using double glazing in windows?

    <p>To minimize heat loss</p> Signup and view all the answers

    How can heat loss through the roof be significantly reduced?

    <p>Fitting loft insulation</p> Signup and view all the answers

    What contributes to heat loss through windows aside from the glass?

    <p>Frame materials</p> Signup and view all the answers

    What is a potential problem with using double glazing that is not the correct size?

    <p>Increased heat loss by conduction or convection</p> Signup and view all the answers

    Which insulation material is commonly used in lofts to minimize convection?

    <p>Mineral wool</p> Signup and view all the answers

    What is the function of rubber seals in modern windows?

    <p>To prevent heat loss from the frame</p> Signup and view all the answers

    Study Notes

    Thermal Energy Transfers

    • Thermal energy is the average kinetic energy of particles.
    • Absolute zero is the lowest achievable temperature (-273°C).
    • At absolute zero, particles have minimum kinetic energy.
    • Thermal energy transfer can occur through conduction, convection, and radiation.

    Conduction

    • Conduction is the transfer of thermal energy through a substance by the vibration of its atoms.
    • It mostly happens in solids due to close-packed particles allowing collisions.
    • Metals are good conductors because of free, delocalized electrons that quickly transfer vibrations.
    • Non-metals, known as thermal insulators, transfer heat much slower. This low thermal conductivity makes them useful in homes.

    Convection

    • Convection is heat transfer through fluids (liquids and gases).
    • Warmer, less dense fluid rises, while cooler, denser fluid sinks.
    • This creates convection currents.
    • Convection does not occur in solids.
    • Faster convection occurs in gases due to particles having more kinetic energy and lower mass.
    • Convection can be prevented by stopping fluid circulation.

    Radiation

    • Thermal radiation is the transfer of energy through infrared (IR) waves.
    • IR waves travel in straight lines and can travel through a vacuum.
    • All objects emit thermal radiation.
    • The hotter the object, the more IR it emits.
    • Dark, matte surfaces absorb and emit radiation more efficiently than light, shiny surfaces.
    • Shiny surfaces can minimize unwanted energy transfer.

    Investigating Conduction

    • Independent variable: Type of metal
    • Dependent variable: Time taken for a drawing pin to drop
    • Control variables: Same diameter of rods, same amount of wax, same distance from heat source, same starting temperature of rods.

    Investigating Convection

    • Independent variable: Temperature of water
    • Dependent variable: Rate of convection
    • Control variables: Same volume of water, same size/strength of flame, same mass of potassium permanganate crystal.

    Investigating Radiation

    • Independent variable: Colour of surface
    • Dependent variable: Temperature/intensity of infrared radiation
    • Control variables: Leslie cube should be same distance to the infrared detector, and measurements should be taken at even intervals.

    Thermal Equilibrium

    • An object will absorb thermal radiation, making it hotter.
    • As an object gets hotter, it emits more thermal radiation.
    • Eventually, the object reaches thermal equilibrium, emitting and absorbing thermal energy at equal rates and thus having a constant temperature.

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    Related Documents

    Physics Revision Notes - Thermal Energy Transfers PDF

    Description

    Test your knowledge on thermal energy transfers, including conduction, convection, and radiation. Explore key concepts such as absolute zero and the properties of conductors versus insulators. This quiz will help reinforce your understanding of how thermal energy moves through different materials.

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