Q 01/05

In the RGB colour model, purple is made by mixing which two colours of light?

A) Red and blue

B) Red and green

C) Blue and yellow

D) Green and blue

Answer · why

A) Red and blue

Unlike violet, purple has no single wavelength of its own, which is why it is called a non-spectral colour.

Q 02/05

Which colour sits at the short-wavelength end of the visible spectrum, just before ultraviolet?

A) Purple

B) Violet

C) Indigo

D) Magenta

Answer · why

B) Violet

Purple, by contrast, is a mixture and never appears in a rainbow.

Q 03/05

Who divided the visible spectrum into seven named colours in 1704?

A) Robert Hooke

B) Christiaan Huygens

C) Isaac Newton

D) Johann Goethe

Answer · why

C) Isaac Newton

He is said to have picked seven to match the notes of the musical scale.

Q 04/05

Tyrian purple, the dye of emperors, was extracted from what?

A) Beetles

B) Lichen

C) Grape skins

D) Sea snails

Answer · why

D) Sea snails

Predatory rock snails of the Muricidae family secrete it; the smell of the dye works was notorious.

Q 05/05

Tyrian purple takes its name from a city in which ancient civilisation?

A) Phoenicia

B) Egypt

C) Persia

D) Carthage

Answer · why

A) Phoenicia

It has even been suggested that the name Phoenicia itself means land of purple.