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

Red and blue light mixed together give purple on a screen; 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

Isaac Newton, in his 1704 Opticks, named seven spectral colours including indigo; he is said to have chosen seven to match the notes of the musical sc...

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

Phoenicia: Tyre, now in Lebanon, was the Phoenician city whose dye works gave the colour its name; the word Phoenicia itself may come from the Greek f...