Light and Optical Systems: Topics 1-3 Test

Question 1

What is the first basic principle of light?

Answer 1

Light is a form of energy we can see (at least some of the light spectrum)

Question 2

What are the sources of light?

Answer 2

Incandescent, fluorescent, phosphorescent, chemiluminescent, bioluminescent.

Question 3

What are the pro’s of incandescent bulbs?

Answer 3

-They were cheap to make/buy

Question 4

What are the pro’s of fluorescent bulbs?

Answer 4

-They were efficient (with energy)

Question 5

What are the cons of incandescent bulbs?

Answer 5

• They are expensive (to your pocket and the enviroment)

- They are not effcient (with energy)

Question 6

What are the cons of fluorescent bulbs?

Answer 6

-They are expensive (to the enviroment and your pocket for getting (rid of) them)

Question 7

What is the first step for calculating the cost of lighting?

Answer 7

1) watts÷1000 = kW

Question 8

What is the second step for calculating the cost of lighting?

Answer 8

2) kW x hours = kWh of energy

Question 9

What is the third and final step for calculating the cost of lighting?

Answer 9

3) kWh X ¢/kWh = cost in ¢

Question 10

What is the ray model of light?

Answer 10

Light travels in straight lines (direction/flow of energy)

Question 11

What is the importance of shadows?

Answer 11

Light travels in straight lines (they prove this)

Question 12

How do plane mirrors affect light?

Answer 12

Plane mirrors are flat mirrors that reflect light. … The image produced by a plane mirror that appears “behind” it is called a virtual image. A virtual image is one that forms where light cannot actually reach. The image appears to be as far behind the mirror as the object is in front of the mirror. (virtual image)

Question 13

How do convex mirrors affect light?

Answer 13

Convex lenses bring light rays together at a point called the focus so they form real images. (convex mirrors form images that appear much smaller and father away than the object) (virtual image)

Question 14

How do concave mirrors affect light?

Answer 14

Concave mirrors produce real images. … Concave lenses spread light rays apart so they form virtual images. (magnified image)

Question 15

What is refraction?

Answer 15

= bending light when it travels through differing densities.

See page 203 for ray diagrams of refraction. Refer to your handout.

Question 16

What is reflection?

Answer 16

bouncing light

Question 17

Why can you see a reflection in some surfaces but not others?

Answer 17

If there is a flat surface, it reflects the light uniformly.

If the surface is rough, it scatters light or reflects it randomly.

Question 18

What is the law of reflection?

Answer 18

The angle of incidence = the angle of reflection, AND the incident ray, the reflected ray and the normal are all in the same plane.

Question 19

Could you explain the disappearing coin through refraction?

Answer 19

The path of light slows down, refracts, so the light does not reflect back to your eyes. (since the law of reflection is not relevant and they are not equal)