Date post: | 21-Dec-2015 |
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A long, thin light bulb illuminates a vertical aperture. Which pattern of light do you see on a viewing screen behind the aperture?
A long, thin light bulb illuminates a vertical aperture. Which pattern of light do you see on a viewing screen behind the aperture?
Light spreads horizontally due to different parts of the lightbulb
Light spreads vertically as it goes through the vertical aperture
The Plane Mirror – Virtual Image
Reflected rays coming from point P’ – The Virtual; Image Point – s=s’
Two plane mirrors form a right angle. How many images of the ball can you see in the mirrors?
A. 1
B. 2
C. 3
D. 4
A. 1
B. 2
C. 3
D. 4
Two plane mirrors form a right angle. How many images of the ball can you see in the mirrors?
Reflection and Refraction
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θi =θ r
Ptolemy 140 AD
Snell 1621sinθin sinθr
Snell’s law allow us to predict how light is going to bend in going fro air to water n=1.5
Is there a way of thinking that makes this evident and proves its generality -> Fermat
Fermat’s Principle of Least Time
Of all possible paths that light takes to get from one point to another light takes the path that corresponds to the shortest time
AEB=AEB’ Shortest length from A to B
after hitting the mirror is the one that goes as a straight line from A to B’, i.e. ACB’.Notice that ACB has equal incidence and reflection
angles
Angle BCF=Angle B’CF= Angle DCA