Materials and Components problems
- 1. Nickel is a non-magnetic material.
Options- A. True
- B. False Discuss
Correct Answer: False
Explanation:
Nickel is ferromagnetic material.
- 2. An electron is moving around a proton, in a circle of radius R. If flux density in the region is increased from zero to B, the force on the electron is
Options- A.
- B. eR (dB / dt)
- C. eRB
- D.
Discuss
Correct Answer:
- 3. A copper specimen has resistivity equal to 1.8 x 10-8 ohm-m at room temperature. At a temperature of 700 K, the resistivity is likely to be
Options- A. 1.6 x 10-8 ?-m
- B. 2 x 10-8 ?-m
- C. 3 x 10-8 ?-m
- D. 6 x 10-8 ?-m Discuss
Correct Answer: 6 x 10-8 ?-m
- 4. The number of protons in a silicon atom are
Options- A. 4
- B. 8
- C. 12
- D. 14 Discuss
Correct Answer: 14
- 5. A rare gas having N atoms/m3 is subjected to an electric field E. The electric dipole moment per unit volume is proportional to N and E.
Options- A. True
- B. False Discuss
Correct Answer: True
- 6. As the atoms of rare gases become larger, electronic polarizability
Options- A. increases
- B. decreases
- C. remains the same
- D. may increase or decrease Discuss
Correct Answer: remains the same
- 7. Carbon steel has a residual flux density of 1 Wb/m2.
Options- A. True
- B. False Discuss
Correct Answer: True
- 8. Assertion (A): Dielectric constant is independent of temperature unless the temperature is extremely high.
Reason (R): For normal temperatures the number of atoms per unit volume is constant.
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
Correct Answer: Both A and R are true and R is correct explanation of A
Explanation:
For normal temperatures the dielectric constant depends on the number of atoms per unit volume.
- 9. The fact that domains exhibits spontaneous magnetisation is
Options- A. first hypothesis is of Curie
- B. second hypothesis is of Weiss
- C. Curie-Weiss law
- D. Boltzmann's statistics Discuss
Correct Answer: second hypothesis is of Weiss
- 10. The number of protons in a copper atom are
Options- A. 2
- B. 9
- C. 11
- D. 29 Discuss
Correct Answer: 29
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