Electromagnetic Waves

Mr. BoyleChatfield Senior High

Speed of Light

• The speed of light (variable c) is 3 X 10 8 m/s. This is true for the whole

electromagnetic spectrum.

ROY G BIV

Using a Classroom Projector to Study the Properties of Light

Drs. Michael Ottinger and Brian BuckleinMissouri Western State University

St Joseph, MO 64507

Missouri Association of Physics Teachers MeetingNovember 6, 2010

Three Color Image System

Red Image

Blue Image

Green Image

Superimpose Images

Red Lamp

Blue Lamp

Green Lamp

Breaking down the Colors

• The following slides were made by using the “Shapes” drop down in PowerPoint to make two thin rectangular lines.

• The top line was set to white and, using the color setting the bottom line was set to different color combinations.

Please put on your spectral glasses

White

Red

Green

Blue

Yellow = Red + Green

Magenta = Red + Blue

Cyan = Green + Blue

White = Red + Blue + Green

You may remove your spectral glasses

What I look like RGB lamp

What color looks like under Sodium Lamp…

A question

• Winnie the Pooh (the yellow skinned bear) is placed under red light. How will he appear?

The answer

Other colors…

Other colors…

Other colors…

Other colors….

Other colors…

Me under infrared light

Intensity of Light

• Transparent– Light Completely passes through (Glass,

transparency

TranslucentLight partially passes through (frosted glass)

OpaqueLight completely blocked.

Reflection of Light

• Mirrors…

Inverse Square Law of Light

Microwaves (High wavelength)

• Used for communication and to cook food.

• Microwaves work by resonating water molecules.

• Do not put foil in the microwave!

Light is a Particle?

• Radiometer

A demonstration

Light is a wave

• Polarization

Polarization of Projector Light

Diffraction

• A wave property of light…

Light

• A discrete quantity of energy….• It is both a wave and a particle…

Laser

• Light Amplification by Stimulated Emission of Radiation…

Hologram

• An object beam interferes with an image beam…