Discussion
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- Question
The heat developed per m3 per second (W) in a conductor having a conductivity ? and a field E is
Options- A. W = ?E2
- B. W = ?E
- C. W =
- D. W = (?E)0.5
- Correct Answer
- W = ?E2
- 1. Ferromagnetic materials
Options- A. shows spontaneous magnetisation below a certain temperature
- B. have resistivity very high as compared to that of iron
- C. can be used even at microwave frequencies
- D. all of the above Discuss
- 2. Rochelle salt is a ferroelectric material.
Options- A. True
- B. False Discuss
- 3. In molecules of ionic crystals, orientation polarization is zero.
Options- A. True
- B. False Discuss
- 4. In a homogeneous magnetic field H of a solenoid, the core carries a magnetic dipole moment M per unit volume equal to
Options- A. ?0 H
- B. ?r H
- C. (?r - 1) H
- D. ?o?r H Discuss
- 5. Assertion (A): The optical dielectric constant (i.e., ?r at optical frequencies)of ionic dielectrics is less than static dielectric constant.
Reason (R): At optical frequencies, Pi = 0.
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
- 6. The relationship of hysteresis loss to maximum flux density was first determined by
Options- A. C. Steinmetz
- B. G.R. Kirchoff
- C. Mr. Laplace
- D. Mr. Ampere Discuss
- 7. A material which is lightly repelled by a magnetic field is known as
Options- A. diamagnetic material
- B. non-magnetic material
- C. ferromagnetic material
- D. paramagnetic material Discuss
- 8. The field pattern of a solenoid is similar to that of bar magnet.
Options- A. True
- B. False Discuss
- 9. A 200 turn coil has a self inductance of 10 mH. If the number of turns is doubled, all other quantities remaining the same, the self inductance will be
Options- A. 2.5 mH
- B. 5 mH
- C. 20 mH
- D. 40 mH Discuss
- 10. In a specimen of ferromagnetic material, as the flux density is increased from zero to 2.5 T, µr will
Options- A. increase
- B. decrease
- C. first decrease then increase
- D. first increase then decrease Discuss
Materials and Components problems
Search Results
Correct Answer: all of the above
Correct Answer: True
Correct Answer: True
Correct Answer: (?r - 1) H
Correct Answer: Both A and R are true and R is correct explanation of A
Correct Answer: C. Steinmetz
Correct Answer: diamagnetic material
Correct Answer: True
Correct Answer: 40 mH
Explanation:
Inductance is proportional to square of number of turns.
Correct Answer: first increase then decrease
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