Chapter 17.1- What is Light?

Question 1

What is the wave model?

Answer 1

Responsible for the fact that like can act as a wave. It is the most widely applied model.

Question 2

What are wave optics

Answer 2

The study of light as a wave

Question 3

What is the ray model

Answer 3

It tells us that’s light travels as a ray, which is a straight line

Question 4

What are light rays

Answer 4

They’re light that travels in a straight line path

Question 5

What are ray optics

Answer 5

The study of light as a ray

Question 6

What chapter do we focus on ray optics

Answer 6

Chapter 18

Question 7

What is the photon model?

Answer 7

It tells us, that in the quantum world, light can exist as a wave and as a particle. It can wave and travel in a straight line path

Question 8

What are Photons measured in

Answer 8

They are the quanta of light

Question 9

What is diffraction

Answer 9

It is when a wave spreads out to fill a space behind an opening. It is a clear sign that a wave is passing through the opening

Question 10

How does changing the space the wave passes through change the shape of the wave

Answer 10

Diffraction only becomes noticeable when the opening is comparable in size to the wavelength of the wave. Otherwise, like in normal life scenarios, it just travels in a straight line forward with sharp shadows

Question 11

What is a “shadow”

Answer 11

It is a defined region where there are no waves

Question 12

What kind of wave is light?

Answer 12

An electromagnetic wave

Question 13

Does light require a medium to travel?

Answer 13

No, because it is a self-sustaining oscillation. It requires no material medium in order to travel

Question 14

Does light require a vacuum?

Answer 14

Yes. All electromagnetic waves, including light waves, travel in a vacuum at the same speed

Question 15

What does c stand for

Answer 15

C is the symbol used to designated the speed of light

Question 16

What speed do light particles travel at

Answer 16

The speed of light, c

Question 17

What is the visible spectrum

Answer 17

400-700 nm, anything outside of this region are not visible to the human eye

Question 18

Do light waves speed up, slow down, or does their speed remain the same as they pass through transparent materials?

Answer 18

Light waves slow down when they pass through transparent materials such as water, glass, or air.

Question 19

Why do light waves slow down when they pass through transparent materials

Answer 19

It is due to the reactions between the electromagnetic field of the the wave and the electrons in the material

Question 20

What is the speed of light in a material characterized by?

Answer 20

The index of refraction, n

Question 21

What is the equation for the index of refraction

Answer 21

The speed of light in a vacuum divided by the speed of light in the material, c / v

Question 22

What is the symbol for the speed of light in a material

Answer 22

v

Question 23

What are two important facts we know about the index of refraction in a material

Answer 23

1. It is always greater than 1, because v is always less than c
2. A vacuum has n=1 exactly

Question 24

What happens to the frequency of a light wave as it changes from one medium to another?

Answer 24

IT. DOES. NOT. CHANGE.

Question 25

What do we know about the wavelength of the transparent material compared to the wavelength of the vacuum

Answer 25

That the wavelength in the transparent material is shorter than the wavelength in a vacuum

Question 26

If you’re given the wavelength of the orange light and the mm of the glass it is passing through, how would you find the light speed of the glass?

Answer 26

To find the speed of the glass. The refraction index, n, of light is given to us on the table. I know that n is c/v. So I would divide the speed of light, c, by the glass refraction index, n, and find the speed of the glass, v.

Question 27

If you’re given the wavelength of the orange light and the mm of the glass it is passing through, how would you find how many wavelengths of the light that were inside the glass slide?

Answer 27

First we would need to find the wavelength of the glass in general. This can be found with lambda of the material = lambda of the vac / n.
Then We know that the question wants us to find N. N is used in the equation d = N(Lamda). Then just plug and chug.

Question 28

What is N

Answer 28

N is the number of wavelengths that span a certain distance. Used in the equation d = N(Lamda)

Question 29

When n is greater. Like n=1 compared to n=1.5 you’d see….?

Answer 29

There are more light rays in the 1.5, like count them, there are more in the 1.5 than the 1