Chapter 8 - Light + Optics Flashcards
Réflection
The rebounding of incident light waves at the boundary of a medium
Theta1 = theta2
How are reflected angles measured?
From the normal
What is the equation for focal length?
F = r/2
What equation is used for distance of focal length, image, and object?
1/f = (1/o)+(1/i) = 2/r
Is the image real or virtual if it has a positive distance?
Real
How do you calculate magnetification?
M = - i/o
How can you tell if image is upright or inverted?
+ value is upright
- value is inverted
Remember UV and IR
Upright always virtual
Inverted always real
Réfraction
Bending of light as it passes from one medium to another and changes speed
Snells law
n = c/v
C = speed of light in vacuum
V = speed of light in the medium
What is index of refractino of a vacuum
1
Air : 1.0003
Water: 1.31
Glass: 1.48 - 1.93
Snells law
N1sinø1=n2sinø2
When light enters medium with higher index of refraction, which direction does it bend?
Toward normal
If lower IOR, bends away from normal
What is power?
P = 1/f
+ for converging
- for diverging
What is hyperopia? myopia?
What corrective lens would be used for each?
Hyperopia: farsightedness
- Converging lens
Myopia: nearsightedness
- diverging lens
Biofocal has both! Très cool!
How are power and multiple lens systems compounded?
1/f = 1/f1 + 1/f2 ….
P = p1 + P2 + P3…..
Example: contact lenses
How do contact lenses work?
Cornea of the eye (converging lens) is in contact with a contact lens (either converging or diverging) and their powers are added
What happens if multiple lenses are not in contact?
The image from the last lens becomes the object of another lens.
Ex: microscopes and telescopes
M = m1 x m2 x m3…
What has smaller wavelength red or violet?
Violet has a smaller wavelength than red light and so is bent to a greater extent
