Today’s question is Because it vibrates when electrically charged, what crystal is often used in timepieces?.
Four options are…
Because it vibrates when electrically charged, Quartz crystal is often used in timepieces.
Billions of people use quartz. Only a few realise it. When an electric current is passed into the quartz tuning fork, it vibrates at a high frequency, more than 32,000 times per second. Watchmakers can translate this mechanical ticking into the ticks of a watch by using an electrical circuit.
If quartz crystals are subjected to mechanical stress, they can generate electricity. This ability to convert voltage to and from mechanical stress is called piezoelectricity. Inside of a watch is a tiny piece of quartz that is shaped like a miniature tuning fork.
Quartz is a hard, crystalline mineral composed of silica. The atoms are linked in a continuous framework of SiO₄ silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO₂.
Color: Colorless through various colors to black
Melting point: 1670 °C (β tridymite) 1713 °C (β cristobalite)
Luster: Vitreous – waxy to dull when massive
Specific gravity: 2.65; variable 2.59–2.63 in impure varieties
Mohs scale hardness: 7 – lower in impure varieties (defining mineral)