Engineering Physics Questions and Answers – Piezoelectricity

This set of Engineering Physics Multiple Choice Questions & Answers (MCQs) focuses on “Piezoelectricity”.

1. Piezoelectric effect is when materials produce electric charges when ____________
a) Voltage is applied
b) Mechanical Stress is applied
c) Electric field is applied
d) Magnetic field is applied
View Answer

Answer: b
Explanation: Certain materials produce electric charges on their surface when mechanical stress is applied on them. This effect is called piezoelectric effect.

2. Piezoelectricity means _________________
a) Electric polarization
b) Electric dielectric
c) Pressure electricity
d) Polar dielectric
View Answer

Answer: c
Explanation: The word piezo means pressure. Thus, piezoelectricity is also called pressure electricity as the application of pressure on certain material induces electricity in them.

3. All Piezoelectric materials are Ferroelectric.
a) True
b) False
View Answer

Answer: b
Explanation: All the ferroelectric materials are pyroelectric and piezoelectric but the reverse is not true. Ferroelectricity can occur only in noncentrosymmetric crystals, just like piezoelectricity.
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4. The piezoelectric materials used for converting energy are called as ___________
a) Transition Devices
b) Converter
c) Dielectric
d) Transducer
View Answer

Answer: d
Explanation: The piezoelectric effect is often used to convert electrical energy into mechanical energy and the piezoelectric materials used are called transducers.

5. Piezoelectricity is shown by substances which are ___________
a) Polar
b) Non-polar
c) Symmetric
d) Asymmetric
View Answer

Answer: d
Explanation: Piezoelectricity is shown by the substances which are asymmetric. If a center of inversion is present and it persists even after stress is applied, the net polarization remains zero.
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6. No regular cubic lattice can exhibit piezoelectricity.
a) True
b) False
View Answer

Answer: a
Explanation: A cubic lattice is highly symmetric. Even after the application of stress, it has a center of inversion. Thus, it cannot exhibit piezoelectricity.

7. What is X-Y from the following graph?
X-Y from the following graph is 1 out of 32 symmetry point groups
a) 1
b) 2
c) 3
d) 4
View Answer

Answer: a
Explanation: There are 32 symmetry point groups out of which 21 (X) are Noncentrosymmetric and out of them 20 (Y) are Piezoelectric. Thus, X – Y = 1.
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8. Piezoelectric effect is ___________
a) Isotropic
b) Anisotropic
c) Large in Magnitude
d) Dominating
View Answer

Answer: b
Explanation: Piezoelectric effect is anisotropic. Since there is a lack of a center of inversion and complex structure of piezoelectric, it is different in different directions.

9. Which of the following is the correct expression for Piezoelectric effect?
a) P = Zd + E
b) P = Zd + εoE
c) P = Zd + εoχE
d) P = Zd + dεoχE
View Answer

Answer: c
Explanation: The correct expression for the piezoelectric effect is: P = Zd + εoχE, where P is the polarization, Z is the stress, d is the piezoelectric strain constant, E the electric field and χ the electric susceptibility.
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10. The piezoelectric strain can be shown as ___________
a) deik/dZ
b) deik/dχ
c) deik/dEi
d) deik/dε
View Answer

Answer: c
Explanation: In practice, the tensile or compressional or shear strains develop in different direction due to an applied electric field depending on the crystal orientation and field direction. The expression for strain is: deik/dE.

Sanfoundry Global Education & Learning Series – Engineering Physics.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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