Pysics P1 OCR

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What is Specific heat capacity?
Specific heat capacity is the amount of energy needed to raise the temperature of 1kg of a substance by 1 degree
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What is the equation for specific latent heat?
Energy= Mass times Specific Latent Heat
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Explain why heating a pan of boiling water dose not increase its temperature
Because the heat energy is being used to break the intermolecular bonds rather than raising the temperature
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Explain how heat is transferred through Radiation
Heat is radiated from the sun as infra-red waves and is absorbed by objects
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Explain how heat is transferred through Conduction
When one particle vibrates inside a solid, it bumps into nearby particles, passes on kinetic energy and makes them vibrate. This process continues and the kinetic energy is spread all the way through the solid causing a rise in temperature.
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Explain how heat is transferred through Convection
When you heat up a liquid or gas, the particles move faster and become less dense.The warmer,less dense fluid rises above its colder,denser surroudings. As the warm air rises, colder fluid takes its place. This circulation of fluid is Convection
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How is radiation different to Conduction and Convection?
1)It dose not need a medium(material) to travel through. 2) It can only occur through transparent substances like air,glass and water .
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Describe how heat radiation is used to cook food under a grill
The heat radiated from a grill is absorbed by the surface particles of the food, increasing their kinetic energy. The heat energy is then conducted or convected to more central parts of the food.
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What are 5 ways of saving enerfy in the home?
Loft insulation, Hot water tank jacket, double glaing, Thick curtains(reduces conduction). Cavity walls and Insulation(reduces convection and conduction) Draught proofing(reduces convection)
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What do thermograms show?
Heat loss
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What happens to a wave when it is refracted?
When a wave meets a denser medium at an angle , part of the wave hits the denser layer first and slows down while another part carries on at the first, faster speed for a while. This causes the wave to change direction
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What happens to a wave when it is diffracted?
It spreads out at the edges when they pass through a gap or past an object.
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What effects the amount of diffraction that takes place when a wave passes through a gap or passes an object?
The amount of diffraction depends on the size of the gap relative to the wavelength of the wave. The narrower the gap the more the wave spreads out.
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List the seven different types of electromagnetic waves in order of wavelength(shortest to largest)
Gamma rays, X-rays, Ultra Violet, Visible light, Infra-red,Microwaves, Radio waves
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Explain why Morse code is a digital signal
Because the light it uses is either on or off.
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What are the advantages of using light to communicate?
1)Its a digital signal so there is little interference. 2)Lots of different light signals can be transmitted down a single optical fibre at the smae time,so you dont need many cables.
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Explain the properties of laser beams which makes them a)monochromatic and b)coherent.
a) All the waves in a laser beam are at the same frequency and wavelength. This makes them monochromatic. b) The light waves are all in phase with each other, the troughs and crest line up. This means it is coherent.
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How do CD players use Lasers to read digital information?
The surface of the CD has billions of lands and pits cut into it. A laser is reflected slightly differently from a land and a pit. This difference is picked up by a light sensor. The change in the reflected beam represents the digital "on" and "off".
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What are the uses for infra-red around the home?
-For cooking(grills and toasters) -Remote controls -In security systems
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Explain why radio waves are mainly used for communication
Because radio waves are long, they diffract more. This means that they can travel longer distances and bend (diffract) round the curved surface of the earth.
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What are the advantages and disadvantages of DAB radio?
There is less interference and many stations can be broadcast at the smae frequency(multiplexing) Thereare a limited number of DAB transmitters in the world and the sound quality is not as good
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Describe how satellites are used for communication
A satellite picks up microwaves sent from the earth and beams them in a different direction towards earth.
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What is the difference between analogue and digital signals?
An analogue signal can take any value within a certain range. The amplitude and frequency of an analogue signal vary continuously. A digital signal can only take two values("on" and "off")
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Why are CFCs so bad?
Because they cause the depletion of the Ozone layer. Th Ozone layer absorbs UV radiation. If the Ozone layer depletes then more UV rays will reach us at the surface of the earth and cause skin cancer.
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Name and describe two types of waves produced in an earthquake
P waves( P waves travel through solids and liquids and are faster than S waves) S waves(S waves only travel through solids and are slower than P waves)
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Other cards in this set

Card 2

Front

What is the equation for specific latent heat?

Back

Energy= Mass times Specific Latent Heat

Card 3

Front

Explain why heating a pan of boiling water dose not increase its temperature

Back

Preview of the front of card 3

Card 4

Front

Explain how heat is transferred through Radiation

Back

Preview of the front of card 4

Card 5

Front

Explain how heat is transferred through Conduction

Back

Preview of the front of card 5
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Comments

*Alisha*

Thanks for the notes:-)

*Alisha*

A few spelling mistakes.

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