Karteikarten
Physics - P1
Karten in diesem Stapel (22)
- 1True or False? All objects emit and absorb infrared radiationTrue
- 2Describe how the colour of a surface affects the emission of infared radiation?darker/matt surfaces emit more infrared than light/shiny surfaces
- 3Explain why pipes inside solar panels are painted matt black.Black is a better absorber of infrared, so the piped (and the water inside) heats up quicker.
- 4How are particles arranged in a solid?
- 5How are particles arranged in a liquid?
- 6How are particles arranged in a gas?
- 7Explain in terms of particles, why heating a block of ice causes it to melt and eventually turns into a gas.As the ice is heated, the particles gain energy and vibrate more. Eventually they have enough energy to move out of the regular arrangement and the block changes state to a liquid.The particles in the liquid gain energy and move faster. Eventually they move fast enough to break free from the liquid and so the liquid turns into a gas.
- 8Explain why metals are the best thermal conductors.They contain free electrons which can move through the metal, transferring the energy more quickly.
- 9Describe how a convection current may form inside a kettle.When the water is heated by the element in the base, the water particles gain more energy and move faster. The hotter region expands and so becomes less dense. It rises through the cooler water. More water is drawn in to replace the water which has risen and the process repeats to create a convection current.
- 10List the ways to increase the rate of evaporation in a liquid.-increase the surface are of the liquid
-pass an air current over the liquid (blow on it)
-increase the temperature of the liquid - 11List all the factors that affect the rate of energy transfer away from a hot object.-Temperature difference between object and surroundings
-Surface are and volume
Material
-Nature of the surface it is in contact with - 12How does the temperature difference between objects affect the rate of energy transfer away form a hot object?The Greater the temperature difference, the greater the rate of energy transfer.
- 13How does the surface area and volume affect the rate of energy transfer from a hot object?In general; the greater the surface area compared to the volume, the greater the rate of energy transfer.
- 14How does the material affect the rate of energy transfer from a hot object?Some materials transfer more quickly than others (metals). The colour and finish of the material also affects the infrared radiation it emits (the darker and less shiny the material the more infrared radiation it emits).
- 15How does the Nature of the surface it is in contact with affect the rate of energy transfer fro a hot object?Some materials transfer energy more quickly than others (metals).
- 16Explain how a vacuum flask is able to keep a cold drink cold on a very hot day.Energy is unable to get into the flask to warm the liquid inside. The vacuum flask reduces the energy transfer into the flask.
- 17What are the key parts of a vacuum flask?-Vacuum layer inside the glass vessel
-Shiny silver on both the inside and outside of the glass vessel
-tight screw cap - 18What are the ways you can minimise the energy transfer from a typical home?-Cavity wall insulation
-Loft insulation
-Draft excluders
-Curtains - 19Explain how U-values of loft insulations would help a house owner buy the most effective one?The lower the U-value the better the object is as an insulator.
- 20Double glazing costs £1200. It saves £60 per year. Calculate the payback time.Payback time = cost divided by savings per year
Payback time = £1200 divided by £60
Payback time = 20 years - 21Explain what is meant by the specific heat capacity of a material.The energy required to increase the temperature of 1 kg of the substance by 1*C.
- 22Calculate the energy needed to increase the temperature of 2200 g of water from 20*C to 90*C. Specific heat capacity = 4200J/kg*CSpecific heat capacity
= 2.2 x 4200 x 70
= 646,800 J
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- Karteikarten am Physics - P1, erstellt von annabaynesab am 27/02/2015.
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