click below
click below
Normal Size Small Size show me how
Physics 1a (2011)
AQA GCSE Science
Question | Answer | Explanation (optional) |
---|---|---|
What is a fuel ? | Something we burn to produce thermal energy | e.g. coal, wood, petrol |
Where does the energy stored in fuels come from ? | The Sun | All living things derive their energy from sunlight. |
What are fossil fuels ? | Coal, oil, natural gas. | These took millions of years to form underground. |
Why are fossil fuels non-renewable ? | They cannot be replaced in our lifetime. | The process takes millions of years. |
What are renewable resources? | Wind, wave, tidal, solar, geothermal,hydroelectric. | These will never run out because they do not burn fuel. |
What problems are associated with burning fossil fuels ? | They cause pollution and add carbon dioxide to the atmosphere. | They will run out someday and they also cause global warming. |
Conduction happens only in . . . | Sokids, liquids and gases. | Although most liquids are poor conductors and so are gases. |
Metals are good conductors of heat and electricity because . . . | They contain de-localised electrons. | The electrons are free to move and transport energy throughout the metal. |
Gases and most non-metals are . . . | Poor conductors of heat (and electricity) | because they have no 'free' electrons. |
Poor conductors such as glass and plastic are called . . . | Thermal insulators. | They are chosen because they do not conduct well. |
Convection usually happens in . . . | liquids and gases | because they can FLOW |
The flow of a fluid (liquid or gas) due to convection is called a . . . | convection current | Hot fluid is less dense so rises, transporting thermal energy. |
Radiation is energy which is carried by . . . | electromagnetic waves, such as light, infra red, radio, etc. | There is no such thing as 'heat waves' in Physics. |
Energy from the Sun travels through the vacuum of space as . . . | electromagnetic radiation, mainly visible light. | The Sun also radiates UV, IR, radio and X-rays. |
The Earth absorbs radiation from the Sun. This causes . . . | the temperature to increase during the hours of daylight. | The temperature falls at night when energy is radiated back into space. |
Every object emits . . . | thermal radiation. | The hotter it is the more radiation it emits. |
Infra red radiation can be used in . . . | TV remotes, thermal imaging cameras, security systems. | IR is invisible to our eyes, but a digital camera can see it; shine a TV remote at it. |
Infra red radiation can be detected with a . . . | thermometer with a blackened bulb to absorb the energy. | Black surfaces are good absorbers of radiation. |
The electromagnetic spectrum consists of . . . | Radio, microwaves, infra-red, visible, ultra-violet, X-rays and gamma rays. | Visible light is just a very small part of it. |
The Earth's atmosphere blocks which types of solar radiation? | Ultra-violet, X-rays | It allows light and some infra red to reach the surface. |
What is the 'Greenhouse Effect'? | Long wavelength radiation is absorbed and cannot escape. | The Earth is warmer because of the Greenhoue effect. |
Which gases are 'Greehouse gases' ? | Water vapour, carbon dioxide and methane. | They strongly absorb infra-red radiation from the Earth's surface. |
Why is 'Global Warming' such a bad thing ? | Polar ice is melting and sea levels are rising. | Low lying areas will be flooded. |