Chapter 7: Understanding Light Flashcards

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1
Q

Give two examples of natural light sources

Give two examples of artificial light sources

A

Fire, sun, fireflies, jellyfish

Lightbulbs, glow in the dark watches

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2
Q

What is radiant energy?

A

Light that spreads out or radiates from a natural sources

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3
Q

What is it called when light bends?

A

Refraction

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4
Q

What is the light that bounces of an object called?

A

the reflected ray

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5
Q

What is the normal?

A

The imaginary line perpendicular to a surface

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6
Q

Give an example of radiant energy

A

The energy given of from a light bulb

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7
Q

Transparent
Translucent
Opaque

A

See through
Mostly see through
Can’t see through

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8
Q

Incandescent sources produce a lot of_____

A

heat

95% of the energy given off from an incandescent source is thermal. Its like having a mini heater in your room

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9
Q

Luminous

A

Glowing, gives off it’s own light

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10
Q

What equals the angle of reflection?

A

The angle of incidence

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11
Q

Why should you wear white when its sunny?

A

Because black absorbs heat meanwhile white reflects it

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12
Q

Give three examples of forms of radiant energy

A
Thermal energy (heat)
Chemical energy (food)
Electrical (electricity)
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13
Q

What word can we use to describe the brightness of light?

A

Intensity

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14
Q

Where does the suns energy come from?

A

Nuclear Fusion

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15
Q

Energy transformation for incandescent source

A

Electrical energy -) Thermal energy -) Visible light energy

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16
Q

Energy transformation for fluorescent source

A

Electrical energy -) Energy absorbed by mercury particles -) Ultraviolet energy -) energy absorbed by phosphor particles -) Visible light energy

17
Q

Describe how a phosphorescent source works

A

Stores energy particles for awhile and releases this energy as visible light. This is how we get the glow in the dark radiation.

18
Q

Chemiluminescent

A

Light given off as a by product of a chemical reaction. Example glow stick

19
Q

What are the two basic properties of light?

How does light travel?

A

Light is a form of energy
Light always travels in straight line
(Light is travels in waves)

20
Q

What is reflection?

A

When light bounces of a surface. This is necessary in order to see the object. The rest of the light is abdsorbed

21
Q

What is a light ray that strikes a surface called?

A

Incident Ray

22
Q

When the incident ray is reflected what is it called?

A

The reflected ray

23
Q

What are the laws of reflection?

A
  1. The angle of reflection is equal to the angle of incidence
  2. The incident ray, the normal and the reflected ray are all in the same plane.
24
Q

What is refraction?

A

When light moves from one medium to another

25
Q

Why does light bend?

A

Because it changes speed when it moves between materials with different densities.

26
Q

Statement, VERY IMPORTANT!!!!!!

MEMORIZE!!!!!!!!!!!!!!!!!!!!!

A

When light travels from one medium to a denser one, it will bend toward the normal. When light moves away from the denser medium it bends away from the normal.

27
Q

What is the angle of refraction?

What happens when angle of incidence increases?

A

When light BENDS from moving from one direction to another.

The angle of incidence increases as well BUT no necessarily by the same amount.

28
Q

How does a mirage work?

A

A mirage is when the air near the ground warms up, light from objects at a distance is refracted in a curved path. This causes the illusion of a water surface which is really the image of the sky refracted be warm air near the ground

29
Q

What is light?

A

Light is a form of energy