LIGHT AND COLOURCHAPTER 11

CHAPTER 11 KEY CONCEPTS Visible Light is a part of the

electromagnetic spectrum. Luminous objects produce light; non-

luminous objects do not. The additive colour theory applies to

colours of light. The subtractive colour theory applies to

colours of non-luminous objects A light filter absorbs certain colours of

light and transmits others. Many technologies use light and colour.

11.1 – WHAT IS LIGHT? Light is a form of energy and can be converted in

to electrical energy.

Light travels very fast (300, 000, 000 meters per second) and in a straight line

Light shows wave-like characteristics

Light is transferred through radiation (transfer of electromagnetic energy through matter or space)

Visible light is a mixture of red, orange, yellow, green, blue, indigo, and violet light. ROY. G. BIV

ELECTROMAGNETIC SPECTRUM

Electromagnetic (EM) Spectrum – the classification of EM waves, arranged from lowest energy to highest energy.

Shorter wavelengths have higher energy.

The EM spectrum includes radio waves, microwaves, infrared light, visible light, ultraviolet light, X-Rays, and Gamma Rays

USES OF ELECTROMAGNETIC WAVES RADIO WAVES – AM/FM radio, TV signals,

cell phone communication

MICROWAVES – microwave ovens, telecommunications

INFRARED LIGHT – lasers, remote controls, food lamps, heat lamps

VISIBLE LIGHT – human vision, rainbows, theatre/concert lighting

USES OF ELECTROMAGNETIC WAVES ULTRAVIOLET LIGHT – “black” light,

causes skin to burn or tan, stimulates production of Vitamin D, tanning booths

X-RAYS – medical imaging, security equipment, cancer treatment

GAMMA RAYS – cancer treatment, product of some nuclear decay/waste