# Shared Flashcard Set

## Details

Unit 14
Reflection & Refraction
28
Physics
04/06/2013

Term
 When VL encounters a material, what happens?
Definition
 It is either re-emitted or absorbed and turned into thermal energy
Term
 Can VL be both re-emitted and absorbed?
Definition
 Yes, infact it is more likely
Term
 When the re-emitted light is send back into the medium it came from, what is that called?
Definition
 Reflection
Term
 When the re-emitted light passes through a transparent material; it changes its course before travelling through the material in a strait line, what is called?
Definition
 Refraction
Term
 When light falls on an object, what happens?
Definition
 It excites electrons in the object
Term
 What do enerized electrons do?
Definition
 Re-emit light
Term
 What causes color?
Definition
 The frequency of re-emitted light
Term
 State the Principle of Least Time.
Definition
 "Light will take the path that requires the shortest time"   -Some dude
Term
 State the Law of Refraction.
Definition
 "Light will ba able to travel from point A to point B fastest if the angle of incidence equals the angle of refraction"
Term
 Explain the Law of Reflection.
Definition
 [image]
Term
 If you put a candle infront of a mirror, how many rays of light are emited from the mirror?
Definition
 ∞ from infinite points
Term
 The rays will diverge from the flame, and then what?
Definition
 They diverge from the mirror
Term
 Reminder: The light ray's angle of incedince is ______________________.
Definition
 Equal to the angle of reflection
Term
 The rays appear to be coming from behind the mirror, what are they called?
Definition
 Virtual images
Term
 Compare the real object and the VI.
Definition
 Identical copies, on different sides of the mirror
Term
 Why dont curved mirrors work accurately?
Definition
 Each angle of incidence still equals each angle of reflection, but the size and distance of these VI can change
Term
 What is diffuse reflection?
Definition
 When light falling on a rough surface is reflected in many directions
Term
 What is the speed of light in air?
Definition
 A little bit less than 3×108 m/s
Term
 What is the speed of light in water?
Definition
 3⁄4 of 3×108
Term
 Explain the path of least time with an angled ray. What will happen?
Definition
 [image]
Term
 What will happen with a perpindicular ray?
Definition
 Path of least time = path of shortest distance
Term
 What is the contant for the speed of light?
Definition
 C=3×108
Term
 What is the speed of light in a vacuum?
Definition
 C
Term
 What is the speed of light in any medium?
Definition

Term
 What happens with higher frequency EM waves?
Definition
 The higher the frequency, the slower the speed
Term
 Explain why a prism seperates light colors.
Definition
 [image] The white light goes in, and since the speeds are different, the seperate light colors come out at different times and at different angles.
Term
 What is total internal reflection?
Definition
 [image]Light strikes the boundary between two mediums and is completely reflected
Term
 How does TIR happen?
Definition
 Angle of incedence > critical angle
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