Flashcards
Refraction Basics
Cards in this deck (22)
- 1As light enters a medium that is more optically dense......It slows down and bends towards the normal
- 2As light enters a medium that is less optically dense.....It speeds up and bends away from the normal
- 3Refraction diagram:
- 4Things we need to remember about diagram:i1 > r1
i2 < r2
i2 = r1
r2 = i1
Incident ray and refracted ray are parallel - 5What is the speed of light in a vacuum or in air?3.00 x 10^8 ms-1
(3sf) - 6What does the refraction index (n) tell us?How will it will refract light
(note it has no units) - 7How do we work out refraction index?Speed of light (c) ms-1 / speed of light in substance (cs) ms-1
- 8What is the refraction index of air?n = 1.00
- 9What is Snells law of diffraction?n1 x sinθ1 = n2 x sinθ2
- 10if n1>n2 , this means light will bend....Away from the normal
- 11If n2>n1 , this means light will bend....Towards the normal
- 12Diagram to show locations of θ1 and θ2:
- 13What is the critical angle?Where the light ray is refracted along the boundary of the object
(θc) - 14If the angle of incidence is smaller than the critical angle then....Refraction occurs as normal (may also be a partially reflected ray)
(θ1 < θc) - 15If the angle of incidence is equal to the critical angle then.....The refracted ray runs along the boundary
(θ1 = θc) - 16If the angle of incidence is larger than the critical angle then....Total internal reflection occurs (TIR)
(θ1 > θc) - 17Critical angle diagram (θ1 = θc) :
- 18Total internal reflection diagram (θ1 > θc) :
- 19How do we work out the critical angle?sinθc = n2/n1
- 20What are the conditions of total internal reflection?1. n1 > n2
2. Incident angle > θc - 21What other law applies to total internal reflection?Law of reflection (angle of incidence = angle of reflection)
- 22If n1 = 1.33 and n2 = 1.00 , find θcsin-1(1.00/1.33) = 48.8 degrees