About Piezoelectrical Effect:

• Piezoelectric Effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress.
• The piezoelectric effect is very useful in many applications that involve the production and detection of sound, generation of high voltages, electronic frequency generation and ultra-fine focusing of optical assemblies.
• The effect is also used in igniting mechanism for cigarette lighters. Indian scientists have recently proposed an efficient way to induce piezoelectric delta phase in polymer nanoparticles.

Source: ForumIAS