Practice Test

Optics Practice Test

Grade 8

Name: __________________________ Date: _____________

1) Match the word with the appropriate definition

Bioluminescence		The process of emitting light because of a high temperature.
Chemiluminescence		Describes a material that allows some light to pass through, but not enough to produce a clear image.
Incandescence		The process of emitting light for some time after receiving energy from another source
Phosphorescence		The reflection of light off a rough surface. It does not produce an image.
Translucent		Living things turning chemical energy into light energy.
Opaque		The bending of light as it travels through materials of different densities.
Refraction		The process of gas emitting light because of energy being passed through it.
Diffuse reflection		The reflection of light off a smooth, shiny surface.
Regular reflection		The process of turning chemical energy into light energy with little or no change in temperature.
Electric discharge		A material that does not allow any light to pass through it.

2) State which source of light energy is being used in each example

a) A toaster filament glowing red _____________________________________

b) Glow-in-the-dark paint _____________________________________

c) A fire fly emitting light ______________________________________

d) A neon sign ___________________________________

e) A glow stick __________________________________

3) Give three examples of luminous objects and three examples on nonluminous objects

Luminous: ____________________________________________________________________

Nonluminous: __________________________________________________________________

4) In the diagram, label the light source, umbra, and penumbra.

5) Sort the following items into groups that are transparent, translucent, and opaque.

Milk, window, smoke, wood, ice cube, copper plate, plastic wrap, skin, stain glass window, clean water.

6) Give examples of how an interior designer might benefit from a knowledge of diffuse reflection. Describe why regular reflection is not desired in a home.

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7) Explain why light bends as it travels from air into water.

8) Fill in the following table that shows the function of parts of a camera and a human eye.

Function of Parts	Camera Parts	Eye Parts
Focuses light
Controls the amount of light entering
Brings images into focus
Records the image

9) List the six spectral colours

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10) Explain how Isaac Newton proved that white light is made up of many colours

11) Explain the difference between a phosphorescent light source and a fluorescent light source.

12) Why is fluorescent light bulb more energy-efficient than an incandescent light bulb?

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