Try these "busters" to exercise your brain ... they should help you grasp the concepts underlying the properties of light - reflection, refraction, dispersion, polarization, etc. To gain the maximum effect you should attempt to answer them before looking at the answers!
[1] If a clock is held in front of a mirror, its image is laterally inverted left to right. From the point of view of a person looking into the mirror does the image of the second hand rotate in the reverse direction, i.e., counterclockwise? Explain your answer.
[2] A woman stands in front of a flat mirror. What is the minimum (vertical) height necessary for her to see her whole image?
[3] (Here's something we've all experienced but I bet you've never wondered about the explanation!) Rear view mirrors in cars are uncoated on the front surface and silvered on the back surface. When properly adjusted, light from behind you reflects from the silvered surface and into your eyes. Great during the day but not so good at night when the light from behind comes from car headlights! The "problem" is solved by tilting the mirror slightly upward ... the reflected glare from the headlights now no longer shines your eyes but you can still see a much less intense image of the car behind in the mirror. How does that happen?
[4] Why does the light from the Sun or Moon often appear as a column of light on the surface of a lake? What would it look like if the surface were perfectly smooth?
[5] You may notice that at sunset, the setting Sun looks "flattened", as in the picture below.
Can you explain why that is the case?
[6] A diamond is a gemstone famous for its brilliance. Why does a diamond show such brilliance? Why does a diamond lose much of its brilliance if it is placed under water?
[7] A glass prism in air bends light "downwards", as shown in (a) below. Is it possible to bend a ray "upward", as shown in (b)?
Explain your reasoning.
[8] When you look at a fish in an aquarium is the fish in the position it appears? Explain.
[9] You are fishing from a dock and you see a fish in the water. (a) If you have a bow and arrow, should you aim above the fish, at the fish or below the fish to have any chance of spearing it? (b) What about if you are using a laser gun; where would you aim? Explain you reasoning.
[10] Two rays of light converge to a point on a screen. A sheet of plane glass is placed parallel to the screen but in the paths of the converging beams. Does the point of convergence move? Explain your answer.
[11] A beam of blue light is traveling through a glass block. When it reaches the glass/air interface it is totally internally reflected. Red light traveling along the same orignal path is not totally reflected but some it refracted into the air. Is this a sensible scenario? If no, why not ... if, yes, why?
[12] If you look at two closely spaced lines through an angled piece of glass, as shown below:
how do the lines appear? For example, do they appear closer together, farther apart or unchanged; are they shifted to the left, to the right, or not shifted at all? Explain your reasoning.
[13] When a beam of light shines on two polarizers, arranged with their transmission axes at 90° as shown below, no light reaches the point P.
If a third polarizer, with its transmission axis at 45°, is inserted between the initial two, does any light get through to P?
Explain why or why not.
[14] Imagine you are sitting on the beach at Fort Lauderdale on a sunny day in the early morning. When you look at the ocean at different times during the day, you notice that the effectiveness of your Polaroid sunglasses appears to change. Why is that?
[15] When the Sun is behind dark clouds and there are gaps in the clouds, you will often see sunlight "fanning" out from the gaps as shown below.
You know that the Sun is so far away that the rays should be very closely parallel; so, how come we see beams that are clearly not parallel?
[16] How far away from you is a rainbow?
[17] In the answer to question [16] we saw that a rainbow is really part of a 3-dimensional cone. Normally, we see only part of that cone; but, it is possible to see the whole rainbow, i.e., a circular rainbow?
[18] You are holding a mirror that just allows you to see the whole of your face.
If you move the mirror farther away from you, do see more or yourself, less of yourself or the same amount?