P2 - Radiation and Life Flashcards
Name the types of electromagnetic wave from lowest energy/ frequency to highest
Radio Waves, Micro-Waves, Infrared, Visible Light, Ultra-Violet, X-rays, Gamma Rays
Photons
Packets of electromagnetic energy
Units of intensity are?
J/m2/s
Electrons
Small negatively charged atomic particles
Ions
Positively or negatively charged atoms
Name the 3 types of ionising radiation
High energy ultraviolet, x-rays and gamma rays
What type of radiation is present in the sun
Ultraviolet
What are the problems of ultraviolet radiation
It can cause sunburn and skin cancer
Property of gamma rays in relation to the body
They can pass through the human body easily
Property of x-rays in relation to the body
They pass through muscle but are absorbed by bone
How are radiographers protected from radiation
By lead and concrete screens
You can increase the thermal energy transferred from radiation by…
Increasing it’s exposure time and intensity
The green house effect
When the earth’s radiation is absorbed or reflected back and the earth gets warmer
Principal frequency
The frequency with the greatest intensity
Why has the level of Carbon dioxide steadily increased on the last 200 years?
The burning of fossil fuels as an energy source has increased the rate of release and deforestation to clear land has decreased the rate of absorption
Global warming
The slow increase in the average temperature worldwide due to the greenhouse effect
Because of what do computer models suggest that global warming will result in more extreme weather?
- Increased water vapour in the hotter atmosphere
- Increased convection wind speed
Modulation
The process during which information is used to change the amplitude or frequency of the carrier wave
Noise
Unwanted information which distorts the amplitude of the carrier continuously
Bytes
The unit which digital information is stored as
How many binary digits is a byte?
Eight
Increasing the number of binary digits for a picture … The sharpness of the image
Increases
Increasing the number of binary digits for a picture … Its quality
Increases
Advantage of digital signals
They are easily stored in electronic memories so can be processed by computers
What is the speed of light/ electromagnetic waves through a vacuum?
3 x 10^8 m/s
Speed of light
3.0 x 10^5 km/s or 300,000 km/s
