# P1

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What happens during a convection current?
When air is heated, more energy particles spread apart and the air becomes less dense so it rises. When the air cools down there is less energy so the particles are close together making it more dense so the air will sink.
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What is density?
How much mass their is in a given volume
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What and how does double glazing stop?
It stops conduction because the layer of trapped air is a bad conductor of heat so it will reduce heat loss.
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What and how does cavity wall insulation stop?
It stops conduction because the air trapped inside acts as an insulator.
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What is the equation to work out efficiency?
Efficiency = (useful energy output / total energy input) x 100
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What is the equation for payback time?
Payback time (in years) = cost of insulation / saving each year
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What is temperature?
It is a measurement of hotness on a chosen scale.
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What is heat?
Heat is a measurement of energy on an absolute scale.
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What is specific heat capacity?
The specific heat capacity of a substance is the amount of energy needed to change the temperature of 1 kg of the substance by 1°C. Different substances have different specific heat capacities.
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What is the equation for specific heat capacity?
Heat = mass x SHC x temperate change
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How can you find specific heat capacity?
SHC = heat / mass x temperature change
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What is specific latent heat?
The specific latent heat of a substance is a measure of how much heat energy is needed to melt or boil it. It is the energy needed to melt or boil 1 kg of the substance. Different substances have different specific latent heats.
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How do you calculate specific latent heat?
Energy = mass x SLH
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What are transverse waves?
Transverse waves are when the displacement is at right angles to the direction of the wave.
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What are longitudinal waves?
Longitudinal waves are when the displacement is parallel to the direction of the wave.
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What is the equation for wave speed?
wave speed (v) = frequency (f) x wavelength ( )
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What is the maximum distance a particle moves in a wave?
Amplitude.
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What is the distance between two peaks on a wave called?
Wavelength.
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What is the number of waves per second called?
Frequency.
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What is reflection?
When the waves bounce off of a surface.
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What is refraction?
When waves bend when they pass through a boundary.
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What is diffraction?
When the waves spread out when they pass through a small gap.
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What is the rule of diffraction?
The smaller the gap is, the curvier the waves become. The larger the gap is, the less curvy the waves become.
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What is the electromagnetic spectrum?
It is the same radiation but with different wavelengths.
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What is the order of the electromagnetic spectrum? (from lowest to highest frequency)
Radio waves, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays.
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What is the critical angle?
The smallest angle at which light can be reflected.
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What is the law of reflection?
The angle of incidence is equal to the angle of reflection.
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What is a key fact about white light sources?
They are not in phase (the crests and troughs are all different).
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What are the key facts about mono-chromatic light sources?
They are in phase (the crests and troughs of each ray of light are the same) and there is divergence.
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What are the key facts about laser light sources?
They are in phase and there is a low divergence.
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What do lasers produce?
They produce a narrow, intense beam of light
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What do all the light waves in a laser have?
They all have the same frequency (this is why a laser is one pure colour), they have a low divergence and they are in phase with eachother.
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Why can microwaves cook quicker than infrared radiation?
Microwaves are able to penetrate into the food and cook it from the inside out which is quicker compared to infrared waves which cook from the outside in by passing kinetic energy to all the particles which is slower.
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What causes earthquakes?
Tectonic plate movement. The mantle of the Earth moves because of convection currents driven by the heat of the core. The crust plates are carried along by the convection currents, causing them to move.
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What are S (secondary, shake) waves?
They are transverse, slow moving and travel through solids only.
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What are P (primary, pressure) waves?
They are longitudinal, fast moving and travel through liquids and solids.
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## Other cards in this set

### Card 2

What is density?

#### Back

How much mass their is in a given volume

### Card 3

#### Front

What and how does double glazing stop?

### Card 4

#### Front

What and how does cavity wall insulation stop?

### Card 5

#### Front

What is the equation to work out efficiency?