Basic Electrical Engineering Questions and Answers – Relative Permeability

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This set of Basic Electrical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Relative Permeability”.

1. What is the unit for relative permeability?
a) H-m
b) H/m
c) H2/m
d) No unit
View Answer

Answer: d
Explanation: Relative permeability is the ratio of permeability of the material to the permeability of free space. Since it is a ratio, it does not have any units.
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2. Which of the following expressions is correct with respect to relative permeability?
a) B = µrµ0/H
b) B = µrµ0H
c) B = µr0H
d) B = µrµ0/H2
View Answer

Answer: b
Explanation: For a non magnetic material: B=µ0H. Hence for a material having relative permeability µr, B=µrµ0H.

3. A substance whose relative permeability is less than the permeability of free space is?
a) Diamagnetic
b) Paramagnetic
c) Ferromagnetic
d) Not a magnetic substance
View Answer

Answer: a
Explanation: A diamagnetic material creates a magnetic field opposing that of the external magnetic field and it repels the external magnetic field. Hence its relative permeability is less than that of the free space.
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4. A substance whose relative permeability is more than the permeability of free space is?
a) Diamagnetic
b) Paramagnetic
c) Ferromagnetic
d) Both paramagnetic and ferromagnetic
View Answer

Answer: d
Explanation: Relative permeability=1+Magnetic susceptibility
Since both paramagnetic and ferromagnetic materials have positive susceptibility, their relative permeability is greater than unity i.e. their permeability is more than the permeability of free space.

5. Diamagnetic substances have relative permeability_____________
a) Greater than 1
b) Less than 1
c) Equal to 1
d) Zero
View Answer

Answer: b
Explanation: A diamagnetic material creates a magnetic field opposing that of the external magnetic field and it repels the external magnetic field. Hence it has relative permeability less than 1.
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6. Paramagnetic substances have relative permeability_____________
a) Greater than 1
b) Less than 1
c) Equal to 1
d) Zero
View Answer

Answer: a
Explanation: A paramagnetic material creates a magnetic field which is weakly attracted to that of the external magnetic field. Hence it has relative permeability greater than 1.

7. As the temperature increases up to the Curie temperature, the relative susceptibility of ferromagnetic materials?
a) Increases
b) Decreases
c) Remains constant
d) Becomes zero
View Answer

Answer: a
Explanation: The susceptibility of ferromagnetic materials increases with the increase in temperature and then it decreases when the temperature goes beyond the Curie temperature.
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8. As the temperature increases beyond the Curie temperature, the relative susceptibility of ferromagnetic materials?
a) Increases
b) Decreases
c) Remains constant
d) Becomes zero
View Answer

Answer: b
Explanation: The susceptibility of ferromagnetic materials increases with the increase in temperature and then it decreases when the temperature goes beyond the curie temperature.

Sanfoundry Global Education & Learning Series – Basic Electrical Engineering.

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To practice all areas of Basic Electrical Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia - Founder & CTO at Sanfoundry
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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