Q 01/05

Among edible plants, which leafy vegetable has been found to hold the largest amount of yttrium?

A) Spinach

B) Lettuce

C) Cabbage

D) Chard

Answer · why

C) Cabbage

Cabbage tops the edible list, though the seeds of woody plants hold far more, as much as 700 parts per million.

Q 02/05

Yttrium compounds doped with europium long supplied the red glow in the screens of which household device?

A) Clock radios

B) Digital watches

C) Pocket calculators

D) Television sets

Answer · why

D) Television sets

Television sets used europium for the red itself, while the yttrium host soaked up energy from the electron gun and passed it along.

Q 03/05

A cerium-doped yttrium phosphor is the key ingredient in LEDs that give off which color of light?

A) Amber

B) White

C) Violet

D) Pink

Answer · why

B) White

White LEDs pair a glowing chip with the phosphor, which gives off yellow light that blends with the chip's own.

Q 04/05

A 1987 yttrium compound was the first superconductor to work above the boiling point of which liquefied gas?

A) Helium

B) Hydrogen

C) Nitrogen

D) Neon

Answer · why

C) Nitrogen

Nitrogen boils at 77 K and the compound superconducts at about 93 K, so a cheap coolant could replace costly liquid helium.

Q 05/05

Yttrium oxide keeps the crystals stable in which diamond look-alike widely sold in jewelry?

A) Cubic zirconia

B) Moissanite

C) Rhinestone

D) Synthetic spinel

Answer · why

A) Cubic zirconia

Cubic zirconia only keeps its cubic crystal form at ordinary temperatures with a stabilizer, typically an oxide of yttrium or calcium.