Unit 2: lesson 10 Flashcards
What does the change in direction of refracted light rays depend on?
The difference in speed between the two mediums.
The index of refraction (n) depends on what factors?
It depends, to a small degree, on the wavelength of the light.
What phenomenon results from the difference in the index of refraction for different colours of light?
Dispersion.
What does dispersion cause when white light passes through a glass triangular prism?
Separation of white light into its spectrum of colours.
What natural occurrence is also a result of dispersion?
Rainbows.
Under what conditions can rainbows form?
When the sun is shining and there are water droplets in the air.
What causes different wavelengths of light to be refracted by different amounts?
Water droplets.
What depends on the position of the observer when viewing a rainbow?
The location of the rainbow.
Fill in the blank: The separation of light into its colours is called _______.
dispersion.
What does the dispersion of light demonstrate?
White light is a combination of all the colours of visible light
This phenomenon can be observed through a prism.
What is light a spectrum of?
Wavelengths and frequencies
Light encompasses various types of electromagnetic radiation.
What part of the light spectrum does visible light represent?
A small part
Other parts include infrared and ultraviolet light.
Name four types of light waves mentioned.
- Radio
- Infrared
- Ultraviolet
- X-rays
These waves differ in their wavelengths and frequencies.
What is the speed of all light waves?
3.00 x 10^8 m/s
This speed is constant for all forms of light in a vacuum.
What is the basis of scattering?
Some of the light must reflect off of particles like dust and lint in the air into our eyes
What happens when light hits particles or molecules in the atmosphere?
It is scattered in all directions by the particle or molecule
What is proportional to the scattering of light in the Earth’s atmosphere?
The fourth power of the frequency (f4)
Which colors of light are scattered more than others in the atmosphere?
Blue light and violet light are scattered much more than red or orange
Why does the sky appear blue?
Because the blue light is being scattered in all directions at the same time
What happens to blue light at sunset?
Much of the blue light is scattered out, making the light reaching the surface lacking in blue
What causes the reddish appearance of sunsets?
The remaining light is scattered by larger particles of dust in the lower atmosphere
When is the dependence of scattering on f4 valid?
When the scattering objects are much smaller than the wavelength of the light
What would happen if the atmosphere did not contain oxygen or nitrogen?
The sky would appear quite different
What do clouds contain that affects their scattering of light?
Water droplets or crystals that are much larger
