8C: Light & Optical Systems

Question 1

What are the properties of light?

Answer 1

1. Light is a form of energy.
2. Light exists as tiny particles called photons.
3. Light travels in straight lines called rays.
4. Shadows form when light rays are blocked.
5. Light travels faster than sound
6. Luminous objects give off their own light. Non-luminous objects only reflect light.
7. When light strikes an object, it can be reflected, transmitted or absorbed.

Question 2

What the difference between a non-luminous and luminous object?

Can you provide an example of each?

Answer 2

A luminous object emits or produces its own light rays.

ex) sun, lightbulb, flashlight, tv, etc.

A non-luminous object relies on a luminous object because they must reflect the incoming light rays.

ex) moon, desk, Mr. Foisy, etc

Question 3

When light travels towards an object, three specific things can happen. What are they?

Answer 3

Light can either be:

• Reflected
• Absorbed
• Transmitted (passes through)

Question 4

What is a diffuse reflection?.

Answer 4

Diffuse reflection is the reflection of light from an irregular surface so that an incident ray is reflected at many different angles.

Question 5

What are the colors in the visible color spectrum?

Answer 5

ROYGBIV

-Red, Orange, Yellow, Green, Blue, Indigo, Violet

Question 6

What is the difference between transparent, translucent, and opaque materials?

Answer 6

• Transparent: transmit nearly all of the light.
• Transluscent: transmit some of the light, but scatters it.
• Opaque: do not transmit any light – they block it.

Question 7

What types of surfaces follow the law of reflection and demonsrate regular reflection?

Answer 7

Smooth and shiny surfaces reflect light rays at the same angle.

Question 8

What does this image represent?

Answer 8

The Law of Reflection

(Angle of Incedence=Angle of Reflection)

Question 9

When light is transmitted through a transluscent object it is often refracted. True or False?

Answer 9

True.

Question 10

Absorption means to block light rays. True or False?

Answer 10

True.

(Colored objects appear that way because they absorb some colors but reflect others).

Question 11

White light is made up of 7 different colors. True or False?

Answer 11

True.

Question 12

Explain what happens when white light passes through a triangular prism.

Answer 12

The prism splits the white light into its colors because the white light gets refracted into its primary components. You will be able to witness the visible light spectrum.

Question 13

What are the primary colours of light?

Answer 13

• Red
• Blue
• Green

Question 14

Explain what an incedent ray is.

Answer 14

The ray of incidence is described as the incoming light ray in a ray diagram or optical device.

Question 15

The primary colors of light are cyan, yellow, and blue. True or False?

Answer 15

False.

These colours are created by mixing the 3 primary colours of light (R,B,G).

Question 16

Why can images become visible when light is projected through a gas that contains dust/other particles?

Answer 16

The light becomes blocked by the solid particles and is either absorbed or reflected. In addition, some gases have a different refractive index.

Question 17

What is refraction?

Answer 17

When light rays pass through one object to another the light bends because it changes speed in the different materials (mediums).

Question 18

Lenses are useful because they can refract light rays in a predictable way. True or False?

Answer 18

True.

Question 19

A concave lens is ________ in the middle.

A convex lens is _________ in the middle.

Answer 19

thinner

thicker

Question 21

Where does “bad” light go???

Answer 21

To Prism….