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52 Cards in this Set
- Front
- Back
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Refraction is when ...
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light slows down and bends because glass/water is more dense than air
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Which is the angle of incidence and the angle of refraction?
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45° angle is the angle of incidence
28° angle is the angle of refraction |
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What kind of lens is this?
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Concave
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What kind of lens is this?
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Convex
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In a convex lens the focal point is...
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to far back
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The distance between the focal point and the middle of the lens is the...
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focal length
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In a concave lens the focal point is...
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to close
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Whats the formula for the power of a lens?
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what are the units for 'power of a lens'
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Dioptres, D
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The power of concave lens is
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negative
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The power of convex lens is
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posotive
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You only use - or + if stating the ... nothing else
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POWER
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The ... is at the back of the eye and that where you want the light to hut
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retina
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What does TIR stand for
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total internal reflection
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how do optical fibers work?
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TIR
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When does TIR occur?
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when the angle is bigger than the critical angle and shone through a semi-circular piece of glass
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What are the 2 most significant sources of background radiation?
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Radon gas
Cosmic rays |
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protons have a ... charge
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1+
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neutrons have ... charge
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0
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electrons have a ... charge
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1-
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What are the three type of radiation?
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Alpha
Beta Gamma |
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What charge does an alpha particle have?
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2+
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What charge does an beta particle have?
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1-
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What charge does an gamma wave have?
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no charge
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an alpha particle has ... neutrons and 2 ...
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2
protons |
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a beta particle has ... electron
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1
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Alpha particles are ... and have a ... mass
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slow
massive |
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Beta particles are ... and have a ... mass
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medium speed
tiny |
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Gamma waves are ... and have ... mass
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fast (speed of light)
no |
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Alpha particles have ... of ionising ability and have a ... penetrating power
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lots
weak |
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Beta particles have ... ionising ability and have a ... penetrating power
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medium
medium |
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Gamma waves have ... ionising ability and have a ... penetrating power
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little
high |
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Alpha particles are stopped by
Beta particles are stopped by Gamma waves are stopped by |
paper
aluminium Lead(reduces) |
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What can you use to measure radiation?
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GM tube
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radiation can cause
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cancer
cell death/damage lead to mutations in offspring inflimation |
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Cells are most sencetive to radiation during ... than any other times
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cell division
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What is ionisation?
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Ionisation is adding or removing electrons from atoms
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What are some uses of radiation?
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Chemical tracers to help with medical diagnostics
Smoke detectors Carbon dating kills cancer finding leas in oil pipes |
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What are factors that affect how dangerous radiation is to u?
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Type of radiation
amount of energy which part of your body mass of body part exposed |
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What is the formula for working out absorbed dose?
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D = absorbed dose
E = energy M = mass |
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What is absorbed dose measured in?
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Gy
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What is the formula for equivalent dose
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H= D x W H= equivelent dose
D = absorbed dose W = Weighing factor |
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What is equivelent dose measured in?
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Sv
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What is the weighing factor for
alpha beta slow neutrons gamma |
20
10 2.3 1 |
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Define activity
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the number of nuclei which break up per second
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What is the formula for calculating activity?
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A = activity
N = number of nuclei t = time |
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What is activity measured in?
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Bq (becquerels)
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What is the Half-life
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the half-life is the time taken for half the atoms in a substance to decay
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What is fission?
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fission is when the nucleus of an atom splits into 2 small nuclei
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What is fusion?
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fusion is when two light nuclei fuse together to form one heavier neucleus. In doing this they create a huge amount of ENERGY
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What is a chain reaction?
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A chain reaction is when - neutrons are released from a split nuclei causing more nuclei to split , releasing more neutrons and so on...
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What can cause a nuclei to split
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firing a neutron at it.
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