Flashcards
Physics unit 1.1
Flashcards do conjunto (34)
- 1What is Infra red radiation?Infrared (IR) is invisible radiant energy, electromagnetic radiation with longer wavelengths than those of visible light
- 2What is Infra red radiation also known as?-Thermal radiation
-Heat - 3How is energy transferred through the air?By Electromagnetic waves
- 4Why does a person in front of a fire feel its warmth?Because they are absorbing its heat energy
- 5What happens to objects which absorb infra red radiation faster than they can emit it?The objects heat up
- 6The hotter the object the more...Infra red radiation is radiates per second
- 7Can all objects emit and absorb infra red radiation?Yes
- 8Do dark coloured and matt surfaces absorb and emit infra red radiation faster or slowed than light coloured and shiny surfaces?They absorb and emit infra red radiation faster
- 9Are light coloured and shiny surfaces good reflectors of Infra red radiation?Yes
- 10Shiny surfaces reduce energy transfer by infra red radiation (True or False)True
- 11Why is aluminium foil good at keeping food hot for longer?Because the shiny surface of the foil reflects back the infra red radiation, which is being emitted by the food
- 12Explain why a hot pie placed in a fridge cools downThe pie is at a hotter temperature than the fridge which means it is emitting more infra red radiation than it is absorbing, causing the pie to lose heat and cool down
- 13What are the three states of matter?Solid, liquid and gas
- 14What does kinetic theory state?All matter is made up of small partials that are constantly moving
- 15The higher the temperature the faster/slower the particles move?The faster the particles move
- 16Describe the particles in a solid-They are packed together in a fixed pattern.
-They are constantly vibrating but held in position by attractive forces.
-If the solid is heated the particles vibrate faster and take up more space, which means its expanded. - 17Describe the particles in a liquid-The particles are close together but the forces are not strong enough to hold them in a fixed pattern
-They can move and slide about, which means it can flow and change shape
-Some particles at the surface may have enough energy to break away and become gas(Vapour) - 18Describe the particles in a gas-The particles are very spread apart and have like no forces between them, this is why gas is so easy to compress
-The particles have a rapid, random motion and quickly fill any space available - 19What is evaporation?When a liquid turns into a gas without boiling
- 20What is condensation?When a gas is changed back into a liquid
- 21If you get out of a swimming pool or shower and do not dry off, you begin to feel cold, why is this?The water evaporates, removing energy from the skin, leaving you feel cold
- 22Metals are not better heat conductors than non-metals (true or False)False
- 23Metals have..................that are free to moveElectrons
- 24A poor conductor is a good/bad insulator?Good
- 25How does a polar bear keep warm?A polar bear has a thick layer of fur which traps small pockets of air. The air reduces the energy transferred by conduction, helping to keep the polar bear warm
- 26What is convection?The transfer of thermal energy by the movement of a liquid or gas due to differences in density
- 27+Air particles gain energy and move around more quickly+The particles move apart, taking up more space
- 28The warm air expands, becoming more/less dense than the cooler air above?More
- 29+The warm air rises, pushing cooler, denser air downwards+
- 30Where in a box of food should you place an ice pack?On top, as the cooler more dense air will fall through the box, keeping it cool
- 31What is a U-Value?It measures how good a material is as an insulator
- 32The lower the U-value the lower the insulation provided by a material (True/False)False
(The lower the better the insulation) - 33The higher the U-Value the faster the material will transfer thermal energy (True/False)True
- 34The energy needed to increase the temperature of an object is calculated using the equation....E=MxCxO
Energy transferred=Mass x specific heat capacity x Temperature change
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- FlashCards sobre Physics unit 1.1, criado por annarhodes em 19-02-2016.
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