The production of deformation from voltage is called?

• A. impedance
• B. cogeneration
• C. piezoelectricity
• D. flux

Answer: (C)

Piezoelectricity is the phenomenon where certain materials develop mechanical strain when an electric field (voltage) is applied. In these crystals, applying voltage causes the internal dipoles to align and the lattice to stretch or compress, producing deformation. This effect is harnessed in ultrasound transducers: an alternating voltage makes the piezoelectric crystal vibrate to generate sound waves, and the crystal can also generate a voltage when it is deformed by incoming waves, enabling detection. The effect occurs in crystals with a non-centrosymmetric structure, such as quartz or PZT ceramics.

Impedance is about opposition to alternating current, not deformation from voltage. Flux refers to the flow of a field through a surface, not deformation due to voltage. Cogeneration is simply producing electricity and useful heat together.