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- Question
Macroscopic quantities of a given material
Options- A. are absolutely constant
- B. are a function of temperature
- C. are a function of temperature, pressure field
- D. none of the above
- Correct Answer
- none of the above
- 1. For an insulating material, dielectric strength and dielectric losses should be
Options- A. high and high
- B. low and high
- C. high and low
- D. low and low Discuss
- 2. As the temperature of semiconductor is increased
Options- A. the average number of free charge carriers decreases
- B. the average number of free charge carriers increases
- C. the average number of free charge carriers remains the same
- D. the average number of free charge carriers may increase or decrease Discuss
- 3. Some ceramic materials become superconducting
Options- A. below liquid helium temperature
- B. between liquid helium and liquid nitrogen temperature
- C. above liquid nitrogen but below room temperature
- D. at room temperature Discuss
- 4. The relative permeability of a ferromagnetic material is
Options- A. 1
- B. less than 1
- C. about 10
- D. 1000 or more Discuss
- 5. Magnetic hysteresis phenomenon is explained by
Options- A. motion of domain walls
- B. motion of domain walls and domain rotation
- C. domain rotation
- D. none of the above Discuss
- 6. Assertion (A): Ferrites are very useful at very high frequencies.
Reason (R): Ferrites have high permeability and high resistivity.
Options- A. Both A and R are true and R is correct explanation of A
- B. Both A and R are true but R is not correct explanation of A
- C. A is true but R is false
- D. A is false but R is true Discuss
- 7. If v is velocity of electron, ?0 is absolute permittivity, m is mass of electron, e is charge on electron and r is the radius of orbit of electron in hydrogen atom, the stability of orbit requires the following equation to be satisfied
Options- A.
- B.
- C.
- D.
Discuss
- 8. Assertion (A): For a dielectric, P = ?0(?r - 1) E.
Reason (R): Dipole moment per unit volume is called polarization of dielectric.
Options- A. Both A and R are true and R is correct explanation of A
- B. Both A and R are true but R is not correct explanation of A
- C. A is true but R is false
- D. A is false but R is true Discuss
- 9. Eddy current loss is
Options- A. proportional to frequency
- B. independent of frequency
- C. proportional to (frequency)2
- D. proportional to (frequency)3 Discuss
- 10. Consider the following statement: In case of a superconductor
- B = 0
- ?r is high
- diamagnetism is high
- transition temperature varies with isotopic mass.
Options- A. 1 and 2 are correct
- B. 2, 3, 4 are correct
- C. 1, 3, 4 are correct
- D. 2, 4 are correct Discuss
Materials and Components problems
Search Results
Correct Answer: high and low
Explanation:
An insulating material should have high dielectric strength and low losses.
Correct Answer: the average number of free charge carriers increases
Explanation:
As temperature increases, conductivity of semi- conductors increases.
Correct Answer: below liquid helium temperature
Correct Answer: 1000 or more
Correct Answer: motion of domain walls and domain rotation
Correct Answer: Both A and R are true and R is correct explanation of A
Correct Answer:
Explanation:
Centrifugal force is equal to 
and coulomb force is equal to 
.
and coulomb force is equal to .
For stability they must be equal.
Correct Answer: Both A and R are true but R is not correct explanation of A
Explanation:
The two statements are correct but independent of each other.
Correct Answer: proportional to (frequency)2
Correct Answer: 1, 3, 4 are correct
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