Electromagnetic Waves

Micro Waves
1. Uses: cooking, mobile phones, communications and satellite transmissions (radar)
2. Produced by oscillating electrons in metals
3. Strongly absorbed by water
4. They make molecules of water vibrate which leads to heat
5. Microwaves start heating internally
6. Produced and received by aerials
Infra Red
1. Uses: heating, grills, toasters, remote controls, cable TV, heat treatment and security systems
2. Heat is caused by vibrating atoms and molecules
3. Given out by all objects that have a temperature
4. Can be detected by skin, thermal cameras and thermometers
5. Starts heating from the surface
6. Dark objects emit and absorb more infra-red than white objects
Visible Light
1. Uses: to see, for illumination in torches or lightbulbs, photography and lasers
2. Produced by atoms when electrons change energy levels
3. When an atom absorbs light, an electron moves to a higher energy level
4. The more levels they jump the higher the frequency
Ultra Violet
1. Uses: security markers, fluorescent lamps, washing powder, sunbeds and for disinfecting water
2. Produced when electrons change energy levels
3. You can absorb UV but get visible light (fluorescence)
4. Can ionise atoms and molecules
5. Damages skin and eye cells
6. Makes you blind or gives you skin cancer in large doses
7. Small doses are good
X Rays
1. Source: x-ray tubes
2. Can be detected by photographic film
3. Uses: observing internal structure, people, metal structure, airport security and archeology
4. Absorbed by bone but transmits or passes through air, skin or soft tissue
5. CT scans are more dangerous because they come in a higher dosage
6. Produced by accelerating electrons
7. Can cause ionisation and kill or damage our cells
8. Alters and damages our DNA cells which causes mutation
Gamma Rays
1. Source: radioactive substances like uranium
2. Made when there is a change in the nucleus of the radioactive substance
3. Detected by Geiger-muller tube
4. Uses; getting rid of bacteria, sterilise surgical equipment, detect and treat cancer
5. Used in radiotherapy
6. Partially absorbed by thick lead and concrete
7. Detected by photographic film
8. Dangerous because it kills and/or mutates cells
Radio Waves
1. Used: TV, Radio, Communications, Bluetooth, Satellite transmissions (radar)
2. produced by oscillating electrons in metals
3. Causes electrons in metals to oscillate, making an electrical current or voltage
4. Atoms, electrons or molecules vibrating leads to heat
5. Causes metals to heat up

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Electromagnetic Waves

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