5699880
Description
Flashcards by Michael Priest, updated more than 1 year ago
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Created by Michael Priest
almost 8 years ago
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| Question | Answer |
| Describe conduction in metals | Free electrons gain kinetic energy Transfer energy by colliding with other electrons |
| Describe conduction in non-metals | Atoms gain energy and vibrate faster Atoms collide with other atoms and pass on their energy |
| Describe convection | Particles gain energy and spread out Fluid becomes less dense and rises Cooler denser fluid sinks |
| What is infrared radiation? | Electromagnetic radiation emitted by hot objects |
| What is meant by specific heat capacity? | The energy needed to increase the temperature of 1kg of a material by 1 degree Celsius |
| What is meant by U-value? | How good a material is as an insulator. The lower the U-value the better the insulator. |
| Explain how evaporation causes cooling. | Particles with more energy leave the surface of the liquid lowering the average energy of the remaining particles which lowers the temperature |
| Explain why condensation happens on cold windows | Water vapour transfers energy to the cooler glass Particles move closer together and turn from a gas into a liquid |
| What does conservation of energy mean? | Energy can't be created or destroyed, only changed from one form to another. |
| What does high efficiency mean? | A high proportion (or percentage) of the total energy is usefully transferred. |
| How is a Sankey diagram used to calculate efficiency? | The width of the useful arrow divided by the width of the total energy input. |
| If one kWh costs 12 p and 5 kWh have been used, how much will the total cost be? | 60 p |
| Give an advantage and a disadvantage of generating electricity using nuclear power | Reliable Radioactive waste |
| Give an advantage and a disadvantage of generating electricity using hydroelectric power | Renewable Flooding valleys damages habitats |
| Give an advantage and a disadvantage of generating electricity using solar power | Renewable, no fuel cost Unreliable |
| Give an advantage and a disadvantage of generating electricity using biofuels | Carbon neutral, renewable Large areas of land needed to grow crops |
| What is meant by the 'frequency of a wave'? | The number of waves passing a point each second. |
| What is the unit of frequency? | Hertz |
| When is the Doppler effect observed? | When a source of waves (light, sound or microwave) moves towards or away from an observer. |
| What is a reflected sound wave called? | An echo. |
| Give two similarities between light and sound waves. | Transfer energy Can be reflected Can be refracted Can be diffracted |
| Give two differences between light and sound waves. | Speed Sound needs a medium to travel through (light does not) Light has a shorter wavelength Light has a higher frequency Light is a transverse wave (sound is longitudinal) |
| What does transverse mean? | Oscillations (or vibrations) are at 90 degrees to the direction of energy transfer |
| What does longitudinal mean? | Oscillations (or vibrations) parallel to the direction of energy transfer |
| What does the red shift of light of distant galaxies provide evidence for? | The expanding Universe and the Big Bang theory |
| What is Cosmic Microwave Background Radiation? | Electromagnetic radiation that is left over after the Big Bang that fills the Universe. |
| What is the importance of Cosmic Microwave Background Radiation (CMBR)? | The Big Bang theory predicts the existence of CMBR, no other theory does. |
| If a source of wave moves towards you what happens to the speed, frequency and wavelength of the waves? | Speed unchanged Frequency is higher Wavelength is shorter |
| If a source of wave moves away from you what happens to the speed, frequency and wavelength of the waves? | Speed unchanged Frequency is lower Wavelength is longer |
| What is the Big Bang theory? | A massive explosion from a single point that created the Universe |
| What is the National Grid? | Cables and transformers that connect power stations to consumers. |
| What does a step-up transformer do? | Increases the voltage Decreases the current |
| What does a step-down transformer do? | Decreases the voltage Increases the current |
| How do transformers increase the efficiency of power transmission? | A lower current in power cables, means less energy wasted heating the surroundings |
| What stages are needed to generate electricity in a fossil fuel or nuclear fuel power station? | Fuel used to boil water which turns to steam Steam turns a turbine Turbine turns a generator |
| What is the unit of Power? | Watt |
| What is the unit of specific heat capacity? | J/kg⁰C |
| If energy is measured in kWh, what are units of Power and time measured in? | Power = kW time = hours |
| If energy is measured in J, what are units of Power and time measured in? | Power = W time = s |
| What is the unit for wavelength? | metres |
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