Light & Surfaces Flashcards

All 6 cards in this deck

What is specular reflection?

Reflection from a smooth surface, where parallel rays are all reflected in the same direction, giving a clear image.

What is diffuse reflection?

Reflection from a rough surface, where rays are scattered in many different directions, so no clear image is formed.

True or false? Diffuse reflection happens because the law of reflection is not obeyed at a rough surface.

False. The law of reflection is obeyed at every point, but the surface normals point in different directions, so the rays scatter.

What decides the colour of an opaque object seen in white light?

The wavelengths its surface reflects; the other wavelengths are absorbed.

e.g. a red object reflects red light and absorbs the rest.

What does a colour filter do to white light passing through it?

It transmits its own colour(s) of light and absorbs the other wavelengths.

e.g. a blue filter transmits blue and absorbs the rest.

True or false? A white object looks white because it absorbs all the wavelengths of visible light.

False. It reflects all wavelengths of visible light roughly equally; a black object absorbs them.