Chapter 17.1- What is Light? Flashcards
What is the wave model?
Responsible for the fact that like can act as a wave. It is the most widely applied model.
What are wave optics
The study of light as a wave
What is the ray model
It tells us that’s light travels as a ray, which is a straight line
What are light rays
They’re light that travels in a straight line path
What are ray optics
The study of light as a ray
What chapter do we focus on ray optics
Chapter 18
What is the photon model?
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
What are Photons measured in
They are the quanta of light
What is diffraction
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
How does changing the space the wave passes through change the shape of the wave
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
What is a “shadow”
It is a defined region where there are no waves
What kind of wave is light?
An electromagnetic wave
Does light require a medium to travel?
No, because it is a self-sustaining oscillation. It requires no material medium in order to travel
Does light require a vacuum?
Yes. All electromagnetic waves, including light waves, travel in a vacuum at the same speed
What does c stand for
C is the symbol used to designated the speed of light
What speed do light particles travel at
The speed of light, c
What is the visible spectrum
400-700 nm, anything outside of this region are not visible to the human eye
Do light waves speed up, slow down, or does their speed remain the same as they pass through transparent materials?
Light waves slow down when they pass through transparent materials such as water, glass, or air.
Why do light waves slow down when they pass through transparent materials
It is due to the reactions between the electromagnetic field of the the wave and the electrons in the material
What is the speed of light in a material characterized by?
The index of refraction, n
What is the equation for the index of refraction
The speed of light in a vacuum divided by the speed of light in the material, c / v
What is the symbol for the speed of light in a material
v
What are two important facts we know about the index of refraction in a material
- It is always greater than 1, because v is always less than c
- A vacuum has n=1 exactly
What happens to the frequency of a light wave as it changes from one medium to another?
IT. DOES. NOT. CHANGE.
What do we know about the wavelength of the transparent material compared to the wavelength of the vacuum
That the wavelength in the transparent material is shorter than the wavelength in a vacuum
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?
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.
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?
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.
What is N
N is the number of wavelengths that span a certain distance. Used in the equation d = N(Lamda)
When n is greater. Like n=1 compared to n=1.5 you’d see….?
There are more light rays in the 1.5, like count them, there are more in the 1.5 than the 1
