Lecture 4

Question 1

Light

Answer 1

A narrow band of electromagnetic radiation that can be conceptualized as a wave or a stream of photons
-A waveform when it travels in space

Question 2

Photon

Answer 2

A quantum of visible light (or other form of electromagnetic radiation) demonstrating both particle and wave properties
-As it hits the retina and is transduced in neuronal activity

Question 3

Light Scattering

Answer 3

The redirection of light as it interacts with particles or molecules in a medium, causing the light to deviate from its original path.
-This phenomenon depends on the size, shape, and composition of the particles relative to the wavelength of the light

Question 4

Rayleigh Scattering

Answer 4

The scattering of light by particles much smaller than the wavelength of light, typically occuring in gases.
-It causes shorter wavelengths (e.g. blue) to scatter more than longer wavelengths, explaining phenomena like the blue colour of the sky

Question 5

Mie Scattering

Answer 5

The scattering of light by particles that are comparable in size to the wavelength of light, such as water droplets or dust.
-Unlike Rayleigh scattering, it affects all wavelengths more equally and often results in a white or grayish appearance, such as in clouds or haze

Question 6

Non-Selective Scattering

Answer 6

The scattering of light by particles much larger than the wavelength of light, such as large water droplets in fog.
-This type of scattering affects all wavelengths equally, resulting in a uniform, white appearance.

Question 7

Light Absorption

Answer 7

The process by which light energy is taken up by a material, converting it into other forms of energy, such as heat, rather than being transmitted or reflected

Question 8

Light Reflection

Answer 8

The process by which light bounces of the surface of a material.
-Reflection can be : -Specular Reflection
-Diffus Reflection

Question 9

Specular Reflection

Answer 9

Where light reflects off a smooth surface in a single, predictable direction

Question 10

Diffus Reflection

Answer 10

Where light reflects off a rough surface, scattering in many directions

Question 11

Transmission

Answer 11

The passage of light through a material, where the light continues to propagate without being absorbed or reflected
-E.g. passes straight through glass

Question 12

Refraction

Answer 12

The bending of light as it passes from one medium to another with a different refractive index, changing its speed and direction
-E.g. changes angle from glass to water

Question 13

Polarizing Glasses

Answer 13

Only let light pass with a certain polarity can be used to reduce the total amount of light that reaches the retina

Question 14

Cornea

Answer 14

The transparent, dome-shaped outer layer at the front of the eye that helps focus light onto the retina

Question 15

Anterior Chamber

Answer 15

The fluid-filled space between the cornea and the iris, containing aqueous humor

Question 16

Aqueous Humor

Answer 16

Nourishes the cornea and lens

Question 17

Pupil

Answer 17

The circular opening in the center of the iris that regulates the amount of light entering the eye
-It acts as a diaphragm and is attached to the ciliary muscle via zonular fibers

Question 18

Vitreous Humor

Answer 18

The clear, gel-likesubstance that fills the space between the lens and the retina, helping maintain the eye’s shape and transmitting light to the retina

Question 19

Choroid

Answer 19

The vasular layer between the retina and sclera that provides oxygen and nutrients to the outer layers of the retina

Question 20

Sclera

Answer 20

The tough, white, outer layer of the eye that provides structural support and protection

Question 21

Retina

Answer 21

The thin, light-sensitive tissue lining the back of the eye, where photoreceptor cells (rods + cones) convert light into neural signals for visual processing

Question 22

Optical Infinity

Answer 22

Objects that are at a distance of 20 feet (6 meters) or more from the eye are said to be here and do not require accommodation to be seen distinctly be a healthy eye

Question 23

Emmetropia

Answer 23

When light rays that are coming from objects located at optical infinity are naturally focused on the retina without any anomolies, the eye is in this condition.
-Lens in relaxed

Question 24

Accommodation

Answer 24

The process by which the eye’s lens changes shape, controlled by the ciliary muscles, to focus light on the retina for clear visio at different distances

Question 25

Focal Length (f')

Answer 25

The distance between the optical center of a lens and its focal point (F'), where parallel rays of light converge or appear to diverge -It determines the len's magnifying power and ability to focus on objects at a various distances

Question 26

Presbyopia

Answer 26

An age-related condition where the eye gradually loses the ability to focus on nearby objects . -It is caused by a reduction in the elasticity of the lens and a weakening of the ciliary muscles, which together limit the eye's ability to adjust (accommodate) for near vision -This typically becomes noticeable around the age of 40 -Stiffening of lens -Can't see from close / close objects

Question 27

Hyperopia (Farsightedness)

Answer 27

A refractive error where distant objects appear clearer than near ones because light focuses behind the retina, often due to a shorter eyeball -Can't see from close

Question 28

Myopia (Nearsightedness)

Answer 28

A refractive error where near objects appear clearer than distant ones because light focuses in front of the retina, often due to a longer eyeball -Can't se from far

Question 29

Astigmatism

Answer 29

A refractive error caused by an irregularly shaped cornea or lens, leading to distorted or blurred vision at all distances because light is focused unevenly on the retina -Feels like different pictures of the world are superposed