Waves And Radiation Flashcards
Longitudinal waves
Sound
Definition of ultrasound
Frequencies above 20000Hz
Definition of diffraction
The bending effect of a wave when obstacles are placed in its way
Radio waves
Low frequency
Long wavelength
Gamma ray
High frequency
Short wavelengths
What can radio waves do?
Diffract easily
What are microwaves used for
Send signals up to space
Example of transverse waves
Light
Water
What is infrared used for
Speeds up the healing of muscle tissue
Thermal imaging cameras
What is visible light used for
Lasers
Remove birthmarks and tattoos
What is ultraviolet used for
Treating skin conditions like acne
What are gamma rays used for
Killing cancer cells
What is refraction
The process where the speed of a wave changes as it travels from one medium to a different medium
What is an alpha particle
2 protons and 2 neutrons
Helium nucleus
Beta
A fast moving electron
Gamma
An electromagnetic wave
What is alpha radiation used for
Smoke detectors
What is background radiation
The radiation that is around us all the time
What is Activity
Number of decays each second
What are some safety precautions when dealing with radiation
Limit the time exposed to radiation
Put a distance between yourself and the radioactive source
Use tongs to lift the source
Never bring radioactive sources close to your bode
Store in lead lined box
Wash hands afterwards
What is meant by the term half life
The time taken for the activity of a radioactive source to half its previous value
What is fission
When a neutron is fired at a large unstable uranium nucleus which absorbs the neutron and then splits into two smaller nuclei and then causes a chain reaction
What is fusion
When two smaller nuclei fuse together to form a large nucleus
Advantages of nuclear fission
No greenhouse gases
Stable supply of electricity
Uses a small amount of fuel but creates a large amount of electricity
Disadvantages of nuclear fission
Produces nuclear waste that is dangerous for hundreds of years
Expensive to store nuclear waste
Catastrophic events like earthquakes and tsunamis could cause dangerous radiation emissions
Nuclear power station are expensive to build
Advantages of fusion
No greenhouse gases
No radioactive waste
Hydrogen as a fuel which is easy to source as it is in water
Disadvantages of fusion
Requires temperatures close to the sun to work which is very dangerous
