Light and Colour

Question 1

What is total internal reflection?

Answer 1

● When light is completely reflected back
at a boundary between two mediums
● It occurs when light meets a less dense
medium at an angle of incidence larger
than the critical angle

Question 2

What is the critical angle?

Answer 2

The angle of incidence which causes the

angle of reflection to be 90 degrees.

Question 3

What determines the colour of visible light waves?

Answer 3

The wavelength and frequency of the

light waves.

Question 4

What colour of visible light has the highest

frequency?

Answer 4

Blue

Question 5

What colour of visible light has the largest

wavelength?

Answer 5

Red

Question 6

What is meant by the term ‘specular reflection’?

Answer 6

Rays are reflected from a smooth

surface in a single direction

Question 7

What is meant by the term ‘diffuse reflection’?

Answer 7

Reflection from a rough surface which

causes scattering.

Question 8

How does a red colour filter work?

Answer 8

● A red filter absorbs all wavelengths of
light other than those in the red range
of the spectrum
● This means only red light passes
through the filter

Question 9

What is meant by “opaque?”

Answer 9

Not see-through.

Question 10

What governs the colour of an opaque object?

Answer 10

● Different objects reflect different
wavelengths of light by different
amounts
● The wavelengths that are most
strongly reflected determine the colour

Question 11

What happens to the wavelengths of light that aren’t

reflected by an opaque object?

Answer 11

Any wavelengths that aren’t reflected are

absorbed by the object.

Question 12

What colour does an object appear if all wavelengths

are reflected by equal amounts?

Answer 12

White.

Question 13

What colour does an object appear if all wavelengths

are absorbed?

Answer 13

Black