Light Notes

Light Notes

*I can distinguish between illuminated vs. luminous body.

* I can identify transparent, translucent, and opaque materials.

* I can identify the colors of the visible light spectrum in order and realize these are seen when white light passes through a glass prism.

* I can also identify the 3 primary light colors and the 3 secondary light colors!

Luminous vs Illuminated

Luminous objects are objects that generate their own light. 

Illuminated objects are objects that are capable of reflecting light to our eyes. The sun is an example of a luminous object, while the moon is an illuminated object.

Multiple Choice

Luminous means...

• Gives out its own light
• Reflects light from other things

Multiple Choice

Mirror

• Luminous

• Illuminated

Multiple Choice

Andromeda Galaxy

• Luminous

• Illuminated

Multiple Choice

Burning Candle

• Luminous

• Illuminated

Transparent, Translucent and Opaque

• TRANSPARENT- most all of the light can pass through, you can clearly see through

• TRANSLUCENT - some of the light can pass through, but you can't clearly see through

• OPAQUE - little to NO light can pass through and you can't see see through it

Multiple Choice

A brick is

• transparent

• translucent

• opaque

Multiple Choice

_____?______ materials do not allow light waves to pass through.

• Opaque
• Transparent
• Translucent

Multiple Choice

_____?_____ materials allow some light to partially pass through, but not in a straight path.

• Opaque
• Transparent
• Translucent

Multiple Choice

Allows most light through

• eflection
• Refraction
• Translucent
• Transparent

Multiple Choice

Blurs light as it passes through

• Transparent
• Translucent
• Opaque
• Refraction

Multiple Choice

Allows little to no light through.

• Transparent
• Translucent
• Opal
• Opaque

Reflection

● Law of reflection -

when a light ray
strikes a reflecting
surface, the angle of
reflection equals the
angle of incidence

● Both angles are

measured from the
normal

Regular vs Diffuse Reflection

● If the beam of light falls on a smooth surface the rays

undergo regular reflection (parallel rays reflect parallel)

● If the beam of light falls on a rough surface, the rays

undergo diffuse reflection (parallel rays do not reflect
parallel)

Why is it harder to see when driving at

night after it has rained?

● Answer:

● Because the wet road is a smooth surface

and very little light is reflected back to our eyes

Are the pages of your book smooth

or rough?

● Answer:

● They are rough

● If they were smooth, there would be a lot

more glare and it would be harder to read.

Color (light Waves)

Have you ever wondered what color is?

Multiple Choice

What is the saying that can help you remember the order of the visible spectrum?

• ROYGBIV

• RYOBIVG

• ROYBVIG

• RIBYOVG

Multiple Choice

What does the picture below illustrate?

• Visible Light Spectrum

• Electromagnetic Spectrum

• Frequency Indicator

• Color Line

Light as Waves

• Subtractive Vs. Additive

• Pigments Vs. Light

Primary light colors - Additive process

Each light bulb emits a primary color of light - red (R), green (G), and blue (B). Depending on which primary color of light is used, the paper will appear a different color.

• Cyan = blue + green

• Magenta = red + blue

• Yellow = red + green

• WHITE = Red + Green + Blue

White is not actually a specific color - it is made of ALL colors mixed together

Looking through a prism or white film breaks white light into its 7 component colors

​

What is white light?

Primary pigment colors OPPOSITE of light colors

-think paints, markers, etc.

Subtractive process:

Imagine R (red), B (blue), G (green) but you subtract one color:

Primary pigments: ​

• Subtract red, so primary pigment = cyan

• Subtract blue, so primary pigment = yellow

• Subtract green, so primary pigment = magenta

​Secondary pigments​

• ​Red (subtract 2 green and blue)

• Blue (subtract 2 green and red) MIX ALL PIGMENTS= BLACK

• Green (subtract 2 blue and red)​

​

When light hits a surface it can be:

• REFLECTED - energy of the wave bounces off the material

• ABSORBED - energy of wave is transferred into the material

The color you see comes from the REFLECTED wavelengths of light.

​

Why are objects a certain color?

Multiple Choice

Why does a shirt appear white?

• It absorbs all light wavelengths of light.

• It refracts all light wavelengths of light.

• It reflects all light wavelengths of light.

• It emits all light wavelengths of light.

Labelling

Drag and drop correct color(s) into each box

Drag labels to their correct position on the image

All colors absorbed

No colors absorbed

No colors reflected

All colors, except Red

Red only

All colors reflected

Multiple Choice

Why does a shirt appear black?

• It absorbs all light wavelengths of light.

• It refracts all light wavelengths of light.

• It reflects all light wavelengths of light.

• It emits all light wavelengths of light.

Multiple Choice

What is happening to the red light?

• reflected

• absorbed

• refracted

Multiple Choice

What is happening to every color but red?

• reflected

• absorbed

• refracted

Multiple Choice

White objects reflect all colors of light and black objects absorb all colors of light.

• True

• False

Multiple Choice

The color that we perceive an object has depends on the 

• The light that is reflected by the object.
• The light that is absorbed by the object.
• The light that is transmitted by the object.
• The light that is created by the object.

Multiple Choice

Why does a yellow pencil look yellow?

• The sun emits all colors, but the pencil reflects yellow more than it reflects the other colors

• The sun reflects all colors, but the pencil emits yellow more than it reflects the other colors

• The sun emits all colors, but the pencil reflects yellow less than it reflects the other colors

• The sun reflects most colors, but the pencil emits yellow less than it reflects the other colors

Multiple Choice

Which is true of a green grape?

• It absorbs green light.
• It absorbs white light.
• It reflects green light.
• It reflects white light.

Multiple Choice

What are the three primary colours of light?

• Red,Yellow,Blue
• Red,Green,Yellow
• Red,Green,Blue
• Yellow,Blue,Green

Multiple Choice

This color in the visible part of the spectrum has the lowest energy. 

• Blue
• Green
• Red
• Violet

Multiple Choice

What are the three secondary colors of light?

• Red, Green, Blue
• Green, Yellow, Blue
• Cyan, Magenta, Yellow
• Magenta, Yellow, Black

Multiple Choice

An object appears red because it

• reflects light waves of all colors
• reflects light waves of red
• absorbs light waves of red
• transmits light waves of all colors

Multiple Choice

This color in the visible part of the spectrum has the highest energy.

• Blue
• Red
• Violet
• Yellow

Multiple Choice

What are the actual colors of the rainbow?

• ROYGVIB
• ROYGBV
• ROYGBIV
• ROYGCB

Multiple Choice

When the three primary colors mix they produce?

• Red, Green, Blue

• Black

• White

• Magenta, Yellow, Cyan

Multiple Choice

When the three primary pigments mix they produce?

• Red, Green, Blue

• Black

• White

• Magenta, Yellow, Cyan

Multiple Choice

How do you make a secondary color?

• Mixing primary colors together
• Mixing secondary colors together
• Mixing primary and secondary colors together
• Mixing the complementary colors together

Multiple Choice

How are we able to see the color white?

• All colors except red are absorbed

• All colors are absorbed

• All colors are reflected

• All colors except red are reflected

Multiple Choice

Of the visible spectrum, what color has the longest wavelength?

• Blue

• Green

• Yellow

• Red

• Violet

Multiple Choice

What type of wave does a light wave resemble?

• Transverse wave

• Compressional wave

Multiple Choice

Light is a type of energy that travels as an ______________ ____________.

• Longitudinal Wave

• Electric Current

• Electromagnetic Wave

• Magnetic Wave

Multiple Choice

What happens when light transitions into a new medium?

• Reflection

• Absorbing

• Refraction

• Mirror

Multiple Choice

What is this a picture of?

• Reflection

• Refraction

Multiple Choice

___________ is a form of energy that we can see with our eyes.

• Radio Waves

• Visible Light

• Ultraviolet

• Reflection

Multiple Choice

When magenta, cyan and yellow pigments overlap, they will create what color?

• Red
• Blue
• White
• Black

Multiple Choice

What kind of light is sunlight?

• White Light
• Infrared Light
• Yellow Light
• Red Light

Multiple Choice

A shirt appears yellow under normal white light conditions. What color does it appear if illuminated with cyan light?

• Red

• Green

• Blue

• Yellow

• Black

Multiple Choice

Which of the following is not a primary color of light?

• Blue

• Red

• Yellow

• Green