Question 1 is essentially homework question 23.41. The diagram there is better. Please look at these corresponding homework solutions!
Exam Question 2 is homework question 24.47 with one of the numbers changed.
Exam Question 3 is homework question 25.28.
Exam Question 4 is homework question 26.3.
5. Concept Questions:
i) Distinguish between a virtual image and a real image.
To see an image means to detect rays of light that seem to have come from a point.
For a real image, the light does actually pass through the image. A card or screen placed at the image location will have an image projected on it. A real image can be projected. An example of a real image is the image you see on a movie screen.
For a virtual image, the light does NOT actually pass through the image. A card or screen placed at the image location will NOT have an image projected on it. A virtual image can NOT be projected. An example of a virtual image is the image you see of your own face when you look in a bathroom mirror.
ii) Is light a wave or a stream of particles?
Sir Isaac Newton thought light was a stream of particles which he called "corspuscles". A contemporary, Christian Huygens, thought light was a wave. There was no experimental evidence to support either until 1809. In 1809 a British Physicist named Young did his famous "Young's double slit experiment" which proves light is a wave. However, in 1903 Albert Einstein explained the photoelectric effect in a manner that requires that light is a stream of particles we now call "photons". Einstein received the Nobel Prize for this explanation of the photoelectric effect.
iii) What evidence can you cite that light is a wave?
In 1809 a British Physicist named Young did his famous "Young's double slit experiment" which proves light is a wave.
iv) What advantages does a reflector telescope have over a refractor telescope? That is, what advantages does mirror telescope have over a lens telescope?
As we discussed in class on Friday, all lenses suffer from "chromatic aberration". That is, the dispersion which produces rainbows and spectra from a prism also means that red light and violet light are focused at (slightly) different places. This produces colored shadows in an image. Sir Isaac Newton recognized this problem and invented the reflecting (mirror) telescope. There is no dispersion for reflection so reflecting telescopes do not suffer from the colored shadows or fringes of lens telescope. All modern large telescopes are reflecting telescopses.