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18 Cards in this Set
- Front
- Back
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Define the two types of satalites |
Low polar orbit closer faster less powerful communications needed Geostationary fixed position 24 hour orbit above the equator |
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How do satalites orbit |
Direction of motion is to right angle of acceleration Gravity creates a centripetal force maintaining a height |
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Difference between scalar and vector |
Scalar size only - distance Vector size and direction - displacement |
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SUVAT equations |
V = u + at S = (u + v / 2) x t V^2= u^2 + 2as S = ut + 1/2at^2 |
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How do rockets work |
Fuel burned in combustion chamber have high energy Particles crash into sides creating high pressure The hotter the gas gets the higher the pressure Large force is created due to high frequency of collisions causing lots of changes in momentum |
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Law of conservation of mass |
Total momentum before collision = total momentum after collision |
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Momentum equation |
m1u1 + m2u2 = (m1 +m2)v |
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How different frequency waves interact with the ionosphere |
More than 30GHz - absorbed by dust and rain More than 30MHz - pass through the ionosphere unaffected Less than 30MHz - reflected back towards earth |
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How to achieve greatest diffraction |
Have the gap size the same as wavelength |
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Define the two types of interference |
Constructive = two waves with aligned crests form a wave with greater amplitude Destructive = two waves when the crest of one lines up with the trough of another cancel each other out |
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What is path difference |
Waves from different sources travel different distances Constructive interference requires even path difference Destructive interference requires odd path difference |
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Evidence for light as stream of particles and a wave |
Particles - Newton believed it moved in a straight line with shadows as an example Wave - diffraction , interference patterns |
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What is polarisation and what does Polaroid filter do |
Only happens to transverse waves Forces light to vibrate in only one plane (different directions) A Polaroid filter only lets polarised light through in a certain plane |
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What is refractive index |
How much the material causes light to slow and bend Speed of light in vacuum / speed of light in medium Water 1.3 Glass 1.4 |
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What is dispersion |
White light split into component colours |
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Describe the visible spectrum |
R O Y G B I V Increasing frequency Decreasing wavelength |
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Uses of convex lenses |
Camera - object behind 2F Projector - object behind F Magnifying glass - object in front of F |
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Magnification equation |
image height / object height |
