The Behavior of Light

22.1 Shadows and Reflections

1. What evidence do you have that light travels in a straight line?

First of all, we can see that the shadow of an object is always in the opposite direction the light is coming from, and always continues with the light in a straight line. As well, light doesn’t bend around corners or stuff.

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3. When light is reflected in a mirror, what is special about the angle of the incident and reflected rays?

Their angles to the mirror are the same.

4. Where is the image when you look at something in a mirror?

It appears to be behind the mirror, because of the way light reflects off the mirrior

5. Light travels in straight lines. If you hide just around a corner so that you can’t see your friends, can they see you?

No, as long as you cannot see your friends, they cannot see you because light travels in straight lines, and if you are behind a wall, it will be blocked.

22.1 Reflections by Different Surfaces

1. What can you see in a completely dark room?

Nothing, because there is no light to reflect off anything

2. If you place a lamp in this dark room as a light source, explain how you now see: a) the lamp b) a piece of paper

a) You can see the lamp because it is a source of light, and produces its own light b) there is now a light source that can provide light to reflect off the paper so you can see it

3. What types of mirror could you sue for make-up or shaving? What would be the advantages of each type?

For shaving you might want to use a concave mirror, and the advantage here is that it will give you a magnified image so you can see If you missed anything, and for make-up you could use a convex mirror, and the advantage of that would be you able to see your whole face.

4. If a driver has one convex and one plane rear-view mirror, how would the images in each appear different?

The image in the plane mirror would appear unaltered, while the image in the convex mirror would appear smaller than normal

5. Why could you not use a concave mirror as a rear-view mirror?

Concave mirrors would show you anything that far off it would be smaller and upside down

6. List as many different uses as you can for plane, convex and concave mirrors

Plane: on dresser – rear-view – full size (one in stores)

Convex: rear-view – make-up – stores

Concave: Shaving – Medical - dental