Question

In a gas lighter, mechanical energy is converted into electrical energy by using crystals of barium titanate. Barium titanate is:
A) Piezoelectric but not ferroelectric.
B) Both piezoelectric as well as ferroelectric.
C) Ferroelectric.
D) Neither ferroelectric nor piezoelectric.

Answer 1

Hint: Some materials have the ability to generate an electric potential under mechanical stress is known as piezoelectricity. Ferroelectricity is the ability of some materials to generate spontaneous electric polarization that can be reversed by an external electric field.

Complete answer:
The chemical formula of barium titanate is ${\text{BaTi}}{{\text{O}}_{\text{3}}}$ . It is an inorganic compound. It has the ability to generate an electric potential under mechanical stress. Material which shows this characteristic property is known as a piezoelectric material. So, barium titanate is a piezoelectric material. It is used as a piezoelectric material in microphones and other transducers.
Barium titanate also has spontaneous polarization ability at room temperature so it is also known as a ferroelectric compound.
Due to its ferroelectric and piezoelectric properties, it is used as an uncooled sensor in a thermal camera.
So, as barium titanate has the characteristic property of converting mechanical energy into electrical energy
It is both piezoelectric as well as ferroelectric material.

Thus, the correct option is (B) both piezoelectric as well as ferroelectric.

Additional Information: Barium titanate is available in both powder and crystal form. The structure of barium titanate is perovskite and changes with a temperature change. It is synthesized by the heating titanium dioxide and barium carbonate.

Note: Barium titanate is used as an electrical insulator. It is also used as a dielectric ceramic material in capacitors. The conversion of mechanical energy to electrical energy is known as the piezoelectric effect. Barium titanate is used in a gas lighter due to its property of piezoelectric and ferroelectric. It is spontaneous polarization at room temperature and its curie temperature is 120 degrees Celsius.