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- Question
If a metal specimen has n valence electrons per m3 each having charge e and mass m and t is the relaxations time, the conductivity is
Options- A.
- B.
- C.
- D.
- Correct Answer
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- 1. Assertion (A): Rochelle salt and Barium titanate are both ferroelectric.
Reason (R): Ferroelectric materials exhibit hysteresis effect.
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
- 2. Diamagnetic materials do not have permanent magnetic dipoles.
Options- A. True
- B. False Discuss
- 3. The core of an atom consists of
Options- A. nucleus
- B. nucleus and all orbits
- C. nucleus and inner orbits
- D. none of the above Discuss
- 4. Assertion (A): Relative permittivity is determined by the atomic structure of the material.
Reason (R): Absolute permittivity is determined by the atomic structure of the material.
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
- 5. The wavelength of light emitted by GaAs laser is 8670 x 10-10 m. If h = 6.626 x 10-34 Js, velocity of light = 3 x 108 m/s and eV = 1.602 x 10-19 J, the energy gap in GaAs is
Options- A. 0.18 eV
- B. 0.7 eV
- C. 1.43 eV
- D. 2.39 eV Discuss
- 6. Assertion (A): Intrinsic resistivity of silicon is lower than that of germanium.
Reason (R): Magnitude of free electron concentration in germanium is more than that of silicon.
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. In a conductor the current flow is due to
Options- A. holes
- B. electrons
- C. ions
- D. electrons and ions Discuss
- 8. Assertion (A): The equation D = ?0?rE is applicable only to isotropic materials.
Reason (R): In polycrystalline materials, the directional effects are absent.
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. A dielectric of relative permittivity ?r is subjected to a homogeneous electric field E. The dipole moment P per unit volume is given by
Options- A. P = constant
- B. P = ?0 E
- C. P = ?0(?r - 1) E
- D. P = ?r E Discuss
- 10. As per Matthiessen's rule, the total resistivity r of a conductor can be written as r = ri + aT, where ri and a are constants and T is absolute temperature. At very low temperatures
Options- A. aT = 0
- B. aT > ri
- C. aT ? ri
- D. aT < ri Discuss
Materials and Components problems
Search Results
Correct Answer: Both A and R are true but R is not correct explanation of A
Explanation:
Both the materials exhibit ferroelectric properties. Hysteresis effect is one of the features of ferroelectric materials.
Correct Answer: True
Correct Answer: nucleus and inner orbits
Correct Answer: A is true but R is false
Correct Answer: 1.43 eV
Correct Answer: A is false but R is true
Correct Answer: electrons
Correct Answer: Both A and R are true but R is not correct explanation of A
Correct Answer: P = ?0(?r - 1) E
Correct Answer: aT < ri
Explanation:
At very low temperatures a T ? 0. Since resistivity has a finite value even at low temperature, a T < ri.
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