Q. Crystals of which of the following naturally-occuring substance exhibits both ‘pyroelectric’ and ‘piezoelectric’ properties making it versatile for application in the field of electronics?
Answer: Quartz
Notes: Quartz crystals have piezoelectric properties: they develop an electric potential upon the application of mechanical stress. An early use of this property of quartz crystals was in phonograph pickups. A common piezoelectric use of quartz today is as a crystal oscillator. The quartz clock is a familiar device using the mineral. Quartz is also strongly pyroelectric. Temperature changes create positive and negative charges within the crystal.