Karteikarten
Physics P1 1A
Karten in diesem Stapel (55)
- 1State the three methods of heat transferRadiation, conduction, convection.
- 2What is radiationHeat energy transfer by infrared radiation.
Heat is emitted and absorbed by everything.
Electromagnetic waves are types of radiation. - 3How does the temperature of an object compared to its surroundings effect its rate of radiation?When an object is hotter than its surrounding s it will emit more radiation than it will absorb.
When it is cooler it will absorb more than it emits.
- 4Which surfaces reflect radiation?Light, shiny surfaces.
- 5What surfaces absorb the most radiation?Dark, matte surfaces.
- 6What is a solar panel?They use the suns heat radiation to heat water without using electricity.
- 7Why do solar panels have matte black surfaces?Because matte, dark colors absorb the most radiation.
- 8How do solar panels work?The suns radiation is absorbed by the black surface to heat cold water in black pipes. The shiny inner surface reflects any radiation that has not been absorbed.
- 9Where does radiation take place?It is emitted and absorbed on the surface of objects.
There does not need to be any particle (it can travel through a vacuum. - 10What is conduction?Heat energy transfer through solids.
- 11How does conduction work?When a solid is heated its particles gain more kinetic energy. This enables them to vibrate more. As they vibrate they bump into their neighboring particles passing on their extra kinetic energy which passes on their extra heat energy.
- 12Is conduction faster in more dense or less dense solids?More dense because the particles do not need to vibrate as much to bump into their neighboring particles and pass on their extra kinetic energy (KE).
- 13Why is conduction slower in less dense solids?Because there is more space between the particles so they have to have more KE to be able to vibrate enough.
- 14What is a material that does not conduct heat called?An insulator.
- 15What is a material that does conduct heat called?A conductor.
- 16—Gas
- 17What are the properties of a gas?They fill the space /container.
They have more KE than liquids and solids.
They do not have a fixed position and can move around randomly. - 18—Liquid
- 19What are the properties of a liquid?They have more KE than a solid.
They do not have a fixed shape.
Weak forces of attraction.
Close together and can move randomly. - 20—Solid
- 21What are the properties of a solid?Particles can vibrate around a fixed point.
Particles in a fixed position.
Regular arrangement.
Strong forces of attraction. - 22What is Kinetic Theory?The three states of matter - solid, liquid and gas.
- 23Why are metals good conductors?They have free electron that can move throughout the metal. Because they move all over the metal the bump into particles and pass on their extra KE.
- 24Why does metal feel hotter than wood when they have been in the sun for the same amount of time?The metal can conduct the heat into your hand faster than the wood can.
- 25Why does metal feel cooler than wood if they have been in the cold for the same amount of time?The metal can conduct the heat from your hand faster than the wood can so feels colder.
- 26Where does convection occur?In gases and liquids.
- 27Explain the image.As the water is heated it is given more KE and spreads out becoming less dense. The less dense water rises to the top of the beaker where it is cooler and loses some of its KE. This means the liquid becomes more dense and sinks where it is heated again.
- 28In what container is convection most efficient in?Square or round.
NOT tall, thin ones or shallow, wide ones. - 29Give an example of convection currents in a gas.A radiator heating a room.
- 30Give an example of convection currents in a liquid.In a kettle or saucepan.
- 31What is this an example of?Condensation.
- 32What is condensation?When a gas turns into a liquid.
- 33How does condensation happen?When the particles in a gas (lots of KE) touch a cold surface they transfer some of their energy into the 'cold' particles. By doing this they lose some of their KE and become more dense as they aren't moving around as much so turn into a liquid on they cold surface.
- 34What is this an example of?Evaporation
- 35What is evaporation?When a liquid turns into a gas.
- 36How does evaporation happen?When the particles in a liquid have enough energy they rise to the surface of the liquid. If they can resist the forces of the other liquid particles and are travelling fast enough they can escape the liquid and become a gas particle. However they must also be travelling in the right direction to escape the liquid.
- 37What happens to the temperature of the remaining liquid once evaporation has taken place?The temperature decreases because the particles with the most kinetic (and heat) energy have escaped.
- 38What is the rate of heat transfer?How fast objects lose or gain heat.
- 39How does surface area affect the rate of heat transfer?The larger the surface area of an object the faster the rate of heat transfer.
- 40Why do arctic foxes have small ears?To reduce their surface area and rate of heat transfer.
- 41How does an objects volume affect its rate of heat transfer?The smaller the volume, the faster the rate of heat transfer.
- 42What else can affect the rate of heat transfer, other than surface area and volume?If the material is an insulator or a conductor.
- 43What is an 'effective' method of insulation?A method that has the biggest annual saving.
- 44What are the most 'cost-effective' methods?The methods that have the shortest payback time.
(Usually the cheapest methods) - 45What is 'payback time'?How long it takes for the annual savings to add up to the initial cost.
- 46payback time = cost (£) / annual saving (£) Initial cost: £200 Annual saving: £50 What is they payback time?200 / 50 = 4
Payback time - 4 years - 47What type of heat transfer do thick curtains prevent/stop?Conduction and radiation.
- 48What type of heat transfer does a hot water tank jacket prevent/stop?Conduction and radiation.
- 49What type of heat transfer does loft insulation prevent/stop?Conduction and convection.
- 50What type of heat transfer does cavity wall insulation prevent/stop?Conduction, convection and radiation.
- 51What type of heat transfer do draught excluders prevent/stop?Convection
- 52What do U-Values show us?How fast heat can transfer through different materials.
(A materials rate of heat transfer) - 53What does a low U-Value show us?That that material is a good insulator.
- 54What does a high U-Value show us?That that material is a bad insulator/conductor.
- 55What does a high U-Value show us?That that material is a bad insulator/conductor.
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- Karteikarten am Physics P1 1A, erstellt von Emily Farnworth am 07/05/2015.
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- Emily Farnworth
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