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Flashcards by Usman Rauf, updated more than 1 year ago
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Created by Josh Price
over 9 years ago
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Copied by Usman Rauf
over 9 years ago
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| Question | Answer |
| What are the main primary energy sources that humans use? | Fossil fuels (Oil, Coal, Gas) Nuclear Fuels Biofuels Wind Power Wave Power Radiation from the Sun |
| Why is electricity called a secondary energy source? | Because it must be generated using a primary energy source. |
| What is the definition of a primary energy source? | An energy source which is found or occurs naturally. |
| How do power stations contribute to climate change? | They burn fossil fuels, which produce carbon dioxide. |
| What happens when electric current passes through a component? | Energy is transferred from the power supply to the component and the environment. |
| What is power a measure of? | The rate at which an appliance transfers energy each second. |
| What is the equation for calculating the amount of energy transferred? | Power (W, kW) x Time (S, H) |
| What is the equation for calculating power? | Voltage (V) x Current (A) |
| What does a domestic electricity meter measure energy transfer in? Why? | Kilowatt hours (kWh) A joule is a very small amount of energy. |
| How do you calculate the cost of energy? | Number of units used (kWh) x Price of one unit (p per kWh). |
| How do you calculate the efficiency of an electrical appliance? | Energy (or power) usefully transferred ---------------------------------------------------- Total energy (or power) supplied x 100 |
| How could energy usage be reduced in a personal context? | - Use public transport - Waste less food - Eat less meat - Wear a jumper |
| How could energy usage be reduced in a national context? | - Insulate homes - Build more efficient power stations |
| Why is electricity convenient? | It is easily transmitted over distances and it can be used in many ways. |
| What is mains electricity produced by? | Generators |
| How do generators produce electricity? | A magnet is spun near a coil of wire, which produces an alternating current. |
| How does the size of the current produced by a generator impact the amount of primary fuel it uses? | The bigger the current, the more primary fuel it uses every second. |
| What happens in a power station? | A primary energy source is burned to boil water and make high pressure steam. The steam passes through a turbine, which rotates the generator to produce electricity. |
| What type of waste is formed by a nuclear power station? | Nuclear Waste |
| What does radioactive waste emit? | Ionising radiation |
| What happens with increased exposure to ionising radiation? | Damage to living cells increases eventually leading to cancer or cell death. |
| What is the distinction between contamination and irradiation by a radioactive material? | Contamination occurs when radioactive material land on or gets inside something. Irradiation is exposure to ionising radiation. |
| Why is contamination more dangerous than a short period of irradiation? | Because contamination leads to long term irradiation, which can cause cancer or kill cells. |
| What are the benefits of nuclear power? | - Yields more than the same amount of fossil fuel. - Produces less waste. Doesn't burn fuel, so no CO2 is produced. |
| What are the risks of nuclear power? | - It will increase the amount of irradiation. - Nuclear waste is radioactive for decades. |
| What is the mains electricity voltage to our homes? | 230 Volts |
| Why is electricity distributed at high voltages across the National Grid? | It reduces energy losses because the higher the voltage, the smaller the current needed for the same power output. With a smaller current, less energy is lost due to heating in the wires. |
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