Introduction

Question 1

Point sources

Answer 1

Emit light waves in all directions (ie. 360 degrees) equally if the medium is homogenous

Question 2

Light rays

Answer 2

They are perpendicular/ orthangonal to the light wavefront Wavefront = circles pebbles make

Question 3

Bundle

Answer 3

Collection of rays/wavefronts from a single source

Question 4

Pencil

Answer 4

Cross-section of a bundle and its point source

Question 5

Diverging pencil

Answer 5

See image

Question 6

Light travels

Answer 6

Light will travel L to R

Question 7

Converging pencil

Answer 7

See image

Question 8

Parallel pencil

Answer 8

Made when one is very far away from point source of light Optical infinity - more than 20 ft.

Question 9

Extended object

Answer 9

Made of an infinite number of point sources Each point emits divergent light rays

Question 10

Ideal imaging system

Answer 10

Outgoing (diverging) wavefronts from a point source, converge to a point called the image point

Question 11

Which laws are the basis of geometric optics?

Answer 11

1. Rectilinear propagation of light 2.neighboring rays of light are independent 3. Law of reflection 4. Law of refraction

Question 12

Rectilinear propagation of light

Answer 12

Idea that light travels linearly if media is homogenous

Question 13

Crepuscular rays

Answer 13

Ex. Sunbeam - beams of light seem to radiate from sun

Question 14

Neighboring light rays are independent

Answer 14

Alight rays from an infinitely distant light source travel parallel to one other through space Ie. If 2 rays converge or enter a space, that doesn’t affect the 3rd ray

Question 15

Law of reflection

Answer 15

The angle of incidence (i) = the angle of reflection (i’)

Question 16

What happens when light travels from a less dense to a more dense media?

Answer 16

The velocity decrease NOTE: density directly affects how light travels through the medium

Question 17

Indices of refraction you must know

Answer 17

n(air) = 1 n(water) = 1.33 [same as aqueous humor and vitreous of the eye] n(lens) = varies

Question 18

Law of refraction

Answer 18

n sin i = n’ sin i’ [snell’s law] Greater the differnce between the 2 n, the more bending of light When n = n’ -> no bending of light When n > n’ -> light bends away

Question 19

Left side of optical system

Answer 19

= in front = anterior

Question 20

Right side of optical system

Answer 20

= behind = posterior

Question 21

Object distance

Answer 21

Measured from the optical system to the object

Question 22

Image distance

Answer 22

Measured from the optical system to the image

Question 23

Focal point

Answer 23

Point where parallel light (from infinity) is brought into focus by the lens

Question 24

Focal length

Answer 24

Distance from lens to its focal point

Question 25

Negative distance

Answer 25

Image/ focal point etc. is opposite the direction of light Typically = in front/ anterior = (-) because light travels R->L Distances posterior/ behind lens are positive

Question 26

How our eye sees images

Answer 26