Discussion
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- Question
When temperature is more than ferromagnetic curie temperature, the behaviour of a ferromagnetic material is similar to that of paramagnetic material.
Options- A. True
- B. False
- Correct Answer
- True
- 1. A parallel plate capacitor having C = 200 x 10-12 F has loss dielectric having tan ? = 4 x 10-4. At an ac voltage of f = 106 Hz and peak value 2 V, the dielectric losses are
Options- A. 10-8 W
- B. 10-6 W
- C. 10-4 W
- D. 10-2 W Discuss
- 2. The temperature at which some materials become superconductors is called
Options- A. Transition temperature
- B. Curie temperature
- C. Neel temperature
- D. Onnes temperature Discuss
- 3. In an homogeneous dielectric subjected to an electric field E, the dipole moment per unit volume is ?0(?r - 1) E.
Options- A. True
- B. False Discuss
- 4. If temperature is increased, the temperature coefficient of a metal
Options- A. increases
- B. decreases
- C. may increase or decrease
- D. remains constant Discuss
- 5. Lines of magnetic field attract each other.
Options- A. True
- B. False Discuss
- 6. The quantum numbers associated with electron motion are designed as
Options- A. a, b, c
- B. h, k, l
- C. n, m, l
- D. h, n, l Discuss
- 7. Which of these has lowest dielectric strength?
Options- A. Dry air
- B. Wet air
- C. Cotton
- D. Paper Discuss
- 8. Transformer oil is
Options- A. refined vegetable oil
- B. refined mineral oil
- C. mixture of vegetable and mineral oil
- D. none of the above Discuss
- 9. Resistivity of copper is lower than that of nickel. When a small percentage of copper is added to nickel, the resistivity
Options- A. increases
- B. decreases
- C. may increase or decrease
- D. remains the same Discuss
- 10. For a superconductor, magnetisation M in a field H is
Options- A. extremely small
- B. - H
- C. - I
- D. zero Discuss
Materials and Components problems
Search Results
Correct Answer: 10-6 W
Explanation:
Dielectric losses = v2 ?C tan ?.
Correct Answer: Transition temperature
Correct Answer: True
Correct Answer: decreases
Correct Answer: False
Explanation:
Lines of magnetic field repel each other.
Correct Answer: n, m, l
Correct Answer: Wet air
Explanation:
Cotton and paper have higher dielectric strength than air. Moisture decreases dielectric strength.
Correct Answer: refined mineral oil
Correct Answer: increases
Correct Answer: - H
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