P2 - Radiation and Life Flashcards
Define the intensity of electromagnetic radiation.
The amount of energy arriving at a square metre of surface per second.
Why does the intensity of radiation decrease with distance?
- Photons spread out as they travel.
- Some photons get absorbed by particles.
- Some photons are reflected and scattered by other particles.
How do microwaves protect us from radiation?
They have a metal case and wire screen in the door.
Draw and label The Carbon Cycle.
How can deforestation affect The Carbon Cycle?
- It adds more CO2 to the atmosphere.
- It prevents as much photosynthesis happening, so less CO2 is removed.
How can burning fossil fuels affect The Carbon Cycle?
- It releases carbon dioxide that has been “locked up” ever since.
What knock-on effects can Global warming have?
- Climate change - Crops may not be able to grow in some areas.
- Extreme weather - e.g: Hurricanes.
- Rising sea levels - Melting ice caps and higher sea temperatures may cause sea levels to rise, flooding low-lying land.
How do AM (Amplitude modulation) and FM (Frequency modulation) differ?
- AM changes the carrier wave based on the signal wave.
- FM changes the signal wave based on the carrier wave.
Why are Microwaves used for satellite TV?
- They are reflected well by metals, so satellite dishes are made from metal.
What are the 7 types of radiation in the Electromagnetic Spectrum in order?
- Radio waves.
- Microwaves.
- Infrared waves.
- Visible light.
- Ultraviolet rays.
- X-Rays.
- Gamma rays.
What is “intensity”?
The number of photons delivered per second and the amount of energy each packet contains, i.e: the photon energy.
If a cell is irradiated, what might happen to it?
- Nothing.
- Mutate - can lead to cancer.
- Die - can lead to burns, sickness and even death.
Why are ions dangerous?
Because they are highly reactive and can take part in other chemical reactions.
Name some greenhouse gases.
- Carbon dioxide.
- Water vapour.
- Methane.
- Nitrous oxide.
Why are radio waves used for transmitting radio and TV programmes?
Because they aren’t strongly absorbed by the atmosphere.
Why are visible light and infrared waves used for carrying information?
Because they can travel huge distances down fibre-optic wires without becoming significantly weaker and can be boosted at intervals.
Why are X-Rays used?
Because they are absorbed by dense materials, so can be used to produce shadow pictures of bones and ‘see’ inside of luggage at airport security checks.
What are the benefits of using digital signals?
- Interference can be easily removed because it only has two states.
- No loss in quality over distance.
- No effect in quality during amplification.
