Energy and Light Calculations

Light Energy

Open Ended

What is light?

What is light made of?

• It is also a form energy made of photons.

• Photons are the smallest unit of visible light.

• "photo" means light

Multiple Choice

What is light made of?

• Neutrons

• Photons

• Electrons

• Protons

How does Light Travel?

• It is a electromagnetic wave.

• It travels in straight path.

• It does not need a medium in order to travel.

Multiple Choice

How does light travel?

• As electromagnetic waves

• As sound waves

• As water, but really fast

Multiple Choice

What is the path of light?

• a straight line

• a wavy line

• in bursts

• it is still unknown

Multiple Choice

True or False, light does NOT need a medium to travel.

• True

• False

Parts of an Electromagnetic Wave

• Crest - the highest point of a wave

• Trough - the lowest point of the wave

• Amplitude - the height of the wave

• Wavelength - the distance between crests or troughs

Multiple Choice

What is the peak of an electromagnetic wave called?

• crest

• trough

• wavelength

• amplitude

Multiple Choice

What is the low point of an electromagnetic wave called?

• crest

• trough

• wavelength

• amplitude

Multiple Choice

What is the height of an electromagnetic wave called?

• crest

• trough

• wavelength

• amplitude

Multiple Choice

What is the distance between crests of an electromagnetic wave called?

• crest

• trough

• wavelength

• amplitude

Sources of Light

• Natural source of light

• Artificial source of light

Multiple Choice

Which of the following is a natural source of light?

• Flashlight

• Sun

• Candle light

• Light Bulb

Characteristic of Light

• Intensity

• Color

Brightness

• Qualitative expression of light intensity

• It is a visual perception in which a light source appears to be emitting light or a surface to be reflecting light.

Brightness can be expressed quantitatively using

• Luminous intensity - it is the amount of light that the object produce.

• It is measured in terms of candela.

• The brightness of light depends on how far you are from the source.

Light intensity

• The closer you are to the source of light; the brighter is the light that you will see.

• If you are farther from the source, the dimmer is the light that you will see.

Wavelength

• Red has the longest wavelength or lowest frequency

• Violet has the shortest wavelength or highest frequency

Which color has the longest wavelength? the shortest wavelength?

Which color has the highest frequency? lowest frequency?

Reflection of Light

• Angle of Reflection - light bounces off of an object - angle of light coming in

• Angle of Incidence - angle of the light coming in

• Smooth Surface Reflect light

Absorption of Light

• Light is taken in and not reflected

• Rough surfaces scatter light

Seeing Colors

The color that we see is actually the color of light that is reflected.

We do not see the colors that are absorbed

Refraction of Light

• When light bends

• Light bends when it changes mediums