Discussion
Home ‣ Electronics and Communication Engineering ‣ Materials and Components Comments
- Question
When a ferromagnetic substance is magnetised there are small changes in dimensions. This phenomenon is called
Options- A. hysteresis
- B. magnetostriction
- C. diamagnetism
- D. dipolar relaxation
- Correct Answer
- magnetostriction
- 1. In a metal the probability of a state 0.1 eV below Fermi level being occupied
Options- A. is more than the probability of state 0.1 eV above Fermi level being occupied
- B. is the same as the probability of state 0.1 eV above Fermi level being occupied
- C. is less than the probability of state 0.1 eV above Fermi level being occupied
- D. may be equal to or more or less than the probability of state 0.1 eV above Fermi level being occupied Discuss
- 2. The iron core of a coil is removed so that it becomes an air cored coil. Its inductance will
Options- A. increase
- B. decrease
- C. remain the same
- D. may increase or decrease Discuss
- 3. At T = 0, the resistivity of a perfect single crystal of a metal is
Options- A. 0
- B. low
- C. high
- D. finite Discuss
- 4. From a homogeneous and isotropic dielectric material of dielectric constant ?r, a small volume element is taken out creating a cavity. The field can be kept homogeneous if Di. (i.e., electric flux density inside the cavity) and D0 (i.e., electric flux density outside the cavity) are such that
Options- A. D0 = Di
- B.
- C.
- D. either (a) or (b) Discuss
- 5. If k is Boltzmann's constant and T is absolute temp, then at room temp.
Options- A. kT ≂ 0.025 eV
- B. kT ≂ 0.5 eV
- C. kT ≂ 1 eV
- D. kT ≂ 100 eV Discuss
- 6. Electrical conductivity of metals expressed in ohm-1 m-1 is of the order of
Options- A. 1010
- B. 105
- C. 10-4
- D. 10-6 Discuss
- 7. In a polyatomic gas, the types of polarization which exist together are
Options- A. electronic and orientational
- B. electronic and ionic
- C. ionic and orientational
- D. electronic, orientational and ionic Discuss
- 8. In elemental dielectrics, the orientation and ionic polarization are absent.
Options- A. True
- B. False Discuss
- 9. An electron in a homogeneous magnetic field and having velocity perpendicular to the direction of field moves
Options- A. perpendicular to the field
- B. along the field
- C. along a straight line inclined at 45° to field
- D. in a circular path Discuss
- 10. An homogeneous dielectric material is subjected to an electric field E. If a small cavity is made inside the material, the electric field intensity inside and outside the cavity are different.
Options- A. True
- B. False Discuss
Materials and Components problems
Search Results
Correct Answer: is more than the probability of state 0.1 eV above Fermi level being occupied
Correct Answer: decrease
Explanation:
Because magnetic flux will decrease.
Correct Answer: 0
Explanation:
At absolute zero temperature resistivity of metals is zero.
Correct Answer:
Explanation:
Since the field is homogeneous 
.
.
Correct Answer: kT ≂ 0.025 eV
Correct Answer: 105
Explanation:
Conductivity is reciprocal of resistivity. Since resistivity of metals is around 10-7 ohm-m, conductivity is about 107 ohm-1 m-1. So 105 is the nearest value.
Correct Answer: electronic, orientational and ionic
Explanation:
All the three types of polarization exist in polyatomic gases.
Correct Answer: True
Correct Answer: in a circular path
Correct Answer: False
Explanation:
The electric field intensity inside and outside the cavity are equal.
Comments
There are no comments.More in Electronics and Communication Engineering:
Programming
Copyright ©CuriousTab. All rights reserved.