Physics unit 1 AQA

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Does a hotter object emit more or less radiation?
More
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Dark, matt surfaces are good ....... and ....... of infrared radiation
Absorbers and emitters
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What is the difference between the state of matter of a solid and a liquid?
The particles in a liquid are in contact but are arranged randomly and are less tightly packed compared to a solid
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Why is metal a good conductor?
A metal is a good conductor because they have free electrons that can pass the energy on from particle to particle. Also, the tight structure of a solid means that energy is passed on by energy transfer/
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What is a convection current?
when the warm air is heated it becomes less dense and expands making it rise. This is then replaced by cool air and the cycle continues.
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What is evaporation?
When a liquid turns to a gas
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The rate of evaporation can be increased by what 3 things?
Increased liquid surface area. Increased liquid temperature. Create a draft of air across the liquid.
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What factors can increase the rate of condensation?
Increased surface area. Reducing surface temperature.
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The greater the ....... the greater the rate of energy transfer
Temperature difference
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What is an insulator?
A poor conductor. They are often substances that contain trapped air.
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What is the specific heat capacity?
The amount of energy required to raise 1 kg of substance by 1 degree Celsius.
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Is a low of a high U value better for insulating?
Lower
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Name 3 forms of energy?
Kinetic, gravitational and electrical.
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What is the conservation of energy?
The amount of energy will always be the same. We can not create or destroy it.
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What is a machine?
Something that transforms one form of energy to another.
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What is efficiency measured in?
Joules
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What makes a machine efficient?
When it wastes as little energy as possible.
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What does a Sankey diagram show?
The energy transfer through an appliance. It shows both wasted and useful energy.
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What is power?
The rate at which an appliance transfers energy? It is measured in watts.
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Why do we use kilowatt-hours?
When a company charges for the amount of electrical energy used, there are many large numbers and a joule is too small a unit to use.
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What is a kilowatt-hour?
The amount of energy transferred by a one kilowatt appliance when used for one hour.
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What is payback time?
The time it takes for an appliance or installation to pay for itself in terms of energy saving.
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What is the general idea of how a power station works?
Steam is produced by heating water. The steam then turns a turbine that is coupled with an electrical generator that produces electricity.
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Why do we want to reduce our use of fossil fuels?
They are nonrenewable and will eventually run out.
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Name 4 renewable energy sources.
Wind power, tidal power, geothermal power and solar power.
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Is nuclear power renewable?
No
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Why are there step up transformers in the national grid?
They increase the voltage before it is transmitted across the grid. They do this so that there is less energy wastage in the cables and the system is more efficient. A step down transformer makes it safe for use at home.
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What type of power station has the shortest start up time?
Gas
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What way do the oscillations travel in a transverse wave?
Perpendicular to the direction of wave travel
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What is a longitudinal wave made up of?
Compressions and rarefactions
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What type of waves are the electromagnetic spectrum?
Transverse
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What type of wave is longitudinal?
Sound
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What is the wavelength?
The distance from one crest to the next crest.
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The angle of incidence always equals what?
The angle of reflection
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What type of image can be formed on a screen?
A real image
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What happens to light when it enters a more dense substance?
Slows down and changes direction towards the normal. This is refraction
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What is diffraction?
The spreading of waves when they pass through a gap or around an obstical.
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What is sound caused by?
Mechanical vibrations
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What does the pitch of a sound wave depend on?
Frequency
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What is the smallest wave in the electromagnetic spectrum?
Gamma
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Can electromagnetic waves travel through a vacuum?
Yes
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What are microwaves used for?
Satellite signals for our mobile phones.
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What is an optical fibre?
A thin glass fibre that transmits signals carried by visible light or infrared radiation by using total internal reflection.
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What is the Doppler effect?
The wavelength and frequency of a wave appear to change according to their proximity to the observer.
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Name 2 sources of evidence to back up the big bang.
Red shift. Cosmic Microwave Background Radiation.
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Other cards in this set

Card 2

Front

Dark, matt surfaces are good ....... and ....... of infrared radiation

Back

Absorbers and emitters

Card 3

Front

What is the difference between the state of matter of a solid and a liquid?

Back

Preview of the front of card 3

Card 4

Front

Why is metal a good conductor?

Back

Preview of the front of card 4

Card 5

Front

What is a convection current?

Back

Preview of the front of card 5
View more cards

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