Post on 31-Mar-2015
Light
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Light is a form of energyCrooke’s Radiometer proves light has energy
Turns in sunlight as the light heats the black side
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Shadows Light travels in a straight line.
If something gets in its path the light is blocked.
A shadow is formed.
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Eclipses
Proves light travels in straight lines
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Light travels in straight lines
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Light on cards goes through if the cards are lined up. This also proves light travels in straight lines
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Reflection
Incident ray
Normal
Reflected ray
Angle of incidence
Angle of reflection
Flat Mirror
Angle of incidence = Angle of reflection
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Image Here in a plane mirror an
image is formed by the eye Can not appear on a screen
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Refraction
Fisherman use a trident as light is bent at the surface
The fisherman sees the fish and tries to spear it
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Refraction through a glass block
Light bends towards the normal
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Real and Apparent Depth
A pool appears shallower
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Focal Point
Focal Point
Lenses Two types of lenses
Converging Lens Diverging Lens
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Dispersion
Breaking up of white light into it’s colours
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Electromagnetic spectrum
Gamma rays
X-rays Ultra violet
Visible light
Infra red Microwaves
Radio/TV
Each type of radiation shown in the electromagnetic spectrum has a different wavelength and a different frequency:
High frequency, short wavelength
Low frequency,long wavelength
γ
The higher the frequency of the wave, the greater its energy. This makes X-rays dangerous and radio waves
safe
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Primary and secondary colours
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UHF and VHF