RAS question
Which of the following is an application of piezoelectric materials?
Correct answer: (B) Converting mechanical stress into electrical energy (used in sensors, igniters, energy harvesting).
Piezoelectric materials are used to convert mechanical stress into electrical energy, which is why they work in sensors, igniters and energy-harvesting devices.
Explanation
Piezoelectricity is the production of electric charge when certain nonconducting crystals are subjected to mechanical pressure. Option B is correct because a piezoelectric material converts mechanical stress into an electrical signal or usable electrical energy. This property drives its practical applications. In sensors, pressure or vibration can be turned into an electrical output; in igniters, a mechanical push can produce the electrical effect needed for ignition; and in energy-harvesting devices, repeated mechanical stress can be tapped for electricity. The converse effect is also part of piezoelectric behavior: an applied electric input can produce mechanical action, which connects piezoelectric materials with actuators and ultrasound transducers.
Why the other options are wrong
- (A) MRI depends on magnetic fields and radio waves, whereas piezoelectricity is about electric charge generated by mechanical pressure.
- (C) Nuclear energy generation is based on nuclear fission, not on the conversion of mechanical stress into electrical energy.
- (D) Optical fibre communication transmits information using light, whereas piezoelectric materials work through a pressure-to-electricity effect.
Concept
This tests the Science and Technology concept of transducer materials: how a material converts one form of energy into another. It recurs in RAS because such applications link basic physics with everyday devices such as sensors, actuators, ultrasound transducers and igniters.