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12 Cards in this Set
- Front
- Back
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What is Infrared radiation? |
Infrared radiation is a type of electromagnetic radiation, which involves waves rather than particles. This means that, unlike conduction and convection, radiation can even pass through transparent materials or through a vacuum. |
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What type of surfaces are better than others at emitting and absorbing infrared radiation? |
Dark, matt surfaces. |
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What type of surfaces are good at reflecting radiation? |
Light coloured, shiny surfaces are good at reflecting radiation. |
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Name 3 uses of infrared radiation. |
Infrared heaters or lamps give out infrared radiation to heat a room PIR’s (passive infra red devices), these can be found as part of home security alarm systems Thermal imaging cameras, police helicopters use these cameras to help find people when flying at night |
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Explain what will happen to the temperature of a hot cup of tea if it is left in a room. |
It will get colder, because it is warmer than it's surroundings and energy will be transferred from the hot liquid to the surroundings. |
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Explain what will happen to the temperature of an ice cold glass of squash if it is left in a room. |
It will get warmer , because energy will be transferred to it from the warmer surroundings. |
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What will eventually happen to the temperature of both hot and cold drinks? |
Both drinks will eventually reach the temperature of the room and no more energy will be transferred. |
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Which drink will emit more infrared radiation, the ice cold squash or the hot cup of tea? |
The cup of tea because it is hotter than the squash, so it radiates more energy. |
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What would be the best colour for an insulated mug? |
White: energy from the hot contents of the mug will be transferred to the mug; if the mug is white it will absorb less of this energy from the hot drink, and emit less of the absorbed energy to the surroundings. |
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In a car park, there are many cars of different colours parked in the sun. Which cars will be the hottest inside? |
Black cars, or cars of other dark colours; dark colours are better at absorbing energy than light colours. |
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How was this image made and how can you use it to determine whether the person is wearing thin or thick clothing? |
The image was made using a thermal camera that detects infrared radiation instead of light. Hot objects radiate more energy than cooler ones, so areas of the image where the camera has detected more infrared radiation represent places at different temperatures. These are shown by different colours with white representing the hottest areas. The temperature of the person’s clothing is similar to the temperature of his/her arms, so it is not acting as an insulator and is therefore likely to be thin. |
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What are the key points of Infrared Radiation? |
Energy is transferred between objects in contact when one object is at a higher temperature than another. Infrared radiation is the transfer of energy by electromagnetic waves. All bodies emit and absorb infrared radiation, and the hotter the body the more infrared radiation it emits. Dark, matt surfaces are good at absorbing and emitting infrared radiation and poor at reflecting it. White shiny surfaces are good at reflecting infrared radiation. They are poor at absorbing and emitting radiation. |
