Module 12: Geometric Optics

Question 1

What is the focal point equation?

Answer 1

f = R / 2
f —> Distance from the mirror to the focal point
R —> Radius of curvature of a spherical mirror

Question 2

What the rules for light traveling through a concave mirror?

Answer 2

1. When a beam of light travels horizontally and hits a spherical, concave mirror, it is reflected so that it passes through the mirror’s focal point.
2. When a beam of light travels through the focal point of a spherical, concave mirror, it is reflected so that it travels horizontally.
3. When a beam of light travels through a spherical, concave mirror’s radius of curvature, it will be reflected backwards along precisely the same path.

Question 3

What is the index of refraction equation?

Answer 3

n = c / v
c —> Speed of light in a vacuum
v —> Speed of light in the medium of interest
n —> Index of refraction

Question 4

What is Snell’s Law of Refraction (hint: it’s an equation)?

Answer 4

n1 * sin(01) = n2 * sin(02)
n1 —> Index of refraction for first medium
n2 —> Index of refraction for second medium
01 —> Angle of incidence
02 —> Angle of refraction

Question 5

What is the index of refraction for air?

Answer 5

The index of refraction for air (to three significant figures) is 1.00

Question 6

What are the rules for light traveling through a converging lens?

Answer 6

Converging lenses rules

1. All light rays that enter the lens traveling horizontally will exit the lens traveling through the focal point
2. All light rays that enter the lens traveling through the focal point will exit the lens horizontally
3. All light rays that enter the lens traveling directly towards the center will experience no deflection as they exit the lens

Question 7

What is the Law of Reflection?

Answer 7

The angle of reflection equals the angle of incidence.

Question 8

Define Virtual Image.

Answer 8

An image formed a the result of extrapolating light beams.

Question 9

Define Real Image.

Answer 9

An image formed as the result of intersecting light beams

Question 10

Define Refraction.

Answer 10

The process by which a light ray bends when it encounters a new medium

Question 11

Define Index of refraction.

Answer 11

The ratio of the speed of light in a vacuum to its speed in another medium

Question 12

Define opaque.

Answer 12

An object through which light cannot travel (eg. a wall).