National 5 - Physics Unit 2 waves & Radiation

Mind Map by , created over 4 years ago

National 5- Unit 2 Waves and Radiation- Mind Map

Created by rachel8899 over 4 years ago
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National 5 - Physics Unit 2 waves & Radiation
1 types of waves?
1.1 Transverse- Particles move up and down at 90 degrees to wave direction. -examples: water waves and electromagnetic spectrum
1.2 Longitudinal- particles move along wave direction -examples: sound waves and ultra sound
1.3 What are waves?
1.3.1 They are created by vibrations and transfer energy
2 Electromagnetic spectrum
2.1 Radio-Microwaves-Infrared-Visible-Ultraviolet-X rays-Gamma
2.1.2 speed=3x10^8ms-1
3 Definitions
3.1 Frequency?
3.1.1 The amount of waves to pass a point in 1 second
3.1.2 equation? f=number/time
3.2 wavelength?
3.2.1 The length of one complete wave (lambda)
3.3 Period?
3.3.1 The time taken to produce one complete wave (seconds)
3.4 Amplitude?
3.4.1 The amount of energy carried by a wave (measured from the mid point to peak or trough)
4 Diffraction?
4.1 When a wave meets an obstacle and bends to some extent.
5 Refraction?
5.1 change in speed of light as it travels from one material to another
5.2 Angle of incidence- between the ray that is entering material and the normal. Angle of refraction- between ray in material and normal. Critical angle- when one ray is parallel to material the le between other ray and normal
5.3 In more dense materials light refracts towards normal. In less dense materials light refracts away from normal
6 Radioactivity
6.1 When is an element radioactive?
6.1.1 When an elements mass number becomes too large its proton-neutron ratio falls out of the band of stability. It begins to emit radiation in order to become stable again
6.2 Alpha
6.2.1 Helium nucleus- 2 protons 2 neutrons -very ionising -absorbed by paper, skin or a few cm of air Polonium-210 used in smoke alrms
6.3 Beta
6.3.1 fast moving electron- ionising -absorbed by few cm of aluminium Strontium-90 used for thickness control
6.4 Gamma
6.4.1 EM wave- least ionising- passes through body -absorbed by several cm of lead Cobalt-60 killing cancer cells
6.5 ionisation?
6.5.1 when an atom looses or gains electrons to become charged
6.6 Activity= the number of radioactive decays each second (Bq)
6.7 Background Radiation
6.7.1 Natural? Rocks Food Cosmic Rays
6.7.2 Artificial? Medical treatments Nuclear waste Weapons testing
6.8 Half-life
6.8.1 the time taken for half the nuclei in a radioactive source to decay
6.9 Precautions
6.9.1 USe tongs, wear gloves, wash hands
6.10 nuclear...
6.10.1 fisson bombarding a uranium atom with a slow neuron producing two or more smaller atoms, fast neutrons, and energy
6.10.2 fusion joining two small nuclei to form a larger nucleus releasing a large amount of energy and no radioactive waste. takes place in sun and stars
7 Dosimetry
7.1 Damage done to tissue depends on...
7.1.1 Type of tissue type of radiation and amount of energy/radiation
7.2 Absorbed Dose
7.2.1 the energy absorbed per unit mass
7.2.2 can reduce it by- shielding, increasing d from source and limiting time with source
7.3 Equivalent dose
7.3.1 the bio harm caused by radiation
7.3.2 We need to measure the rate of this to prevent people from experiencing too much exposure in a short period of time