Light and the Electromagnetic Spectrum

Light as a Wave

• light is a visible form of energy

• most of the energy that surrounds us is invisible

• this energy travels in waves made of electric and magnetic fields

• called “Electromagnetic Radiation”

Light as a Wave

Electromagnetic Spectrum = the entire range of visible and invisible energy waves

Properties of Waves

wavelength

wavelength

amplitude

amplitude

Wavelengths of the Electro-Magnetic Spectrum

Wavelength and Colour

Seeing Colour

Pinhole Camera

How Light is Transmitted

Transparent:

allows light to pass through

Translucent:

allows some light to pass through

Opaque:

allows no light to pass through

Light Reflection

• The reason we see objects is because they reflect light

Smooth Surface

Rough Surface

Reflection in a Plane Mirror

Activity 4.11

How Light Reflects

A

B

Law of Reflection:

When light reflects off a surface, the angle of incidence is always equal to the angle of reflection

i = r

Looking in a mirror

Looking in a mirror

Looking in a mirror

Object distance vs. Image Distance