Discussion
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- Question
The number of valence electrons in germanium atom is
Options- A. 4
- B. 2
- C. 1
- D. zero
- Correct Answer
- 4
- 1. The materials having low retentivity are suitable for making
Options- A. temporary smagnets
- B. weak magnets
- C. permanent magnets
- D. both temporary and permanent magnets Discuss
- 2. Automobile ignition systems use the principle of
Options- A. resistance
- B. self inductance
- C. mutual inductance
- D. capacitance Discuss
- 3. If ?0 is the angular frequency of rotation of electron in the absence of magnetic field, the angular frequency ?, when a magnetic field B is acting is ? ? ?0 + (e/2m)B.
Options- A. True
- B. False Discuss
- 4. When an atom of polarizability a is placed in an electric field E, the energy stored in atom is 0.5 a E2.
Options- A. True
- B. False Discuss
- 5. The mass of proton and electron are
Options- A. 1.672 x 10-26 kg and 9.107 x 10-31 kg respectively
- B. 9.107 x 10-26 kg and 9.107 x 10-31 kg respectively
- C. 9.107 x 10-29 kg and 9.107 x 10-31 kg respectively
- D. 9.107 x 10-30 kg and 9.107 x 10-31 kg respectively Discuss
- 6. The carrier mobility in a semiconductor is 0.4 m2/Vs. Its diffusion constant at 300 K will be (in m2/s)
Options- A. 0.40
- B. 0.16
- C. 0.04
- D. 0.01 Discuss
- 7. Lines of magnetic field attract each other.
Options- A. True
- B. False Discuss
- 8. If temperature is increased, the temperature coefficient of a metal
Options- A. increases
- B. decreases
- C. may increase or decrease
- D. remains constant Discuss
- 9. 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
- 10. The temperature at which some materials become superconductors is called
Options- A. Transition temperature
- B. Curie temperature
- C. Neel temperature
- D. Onnes temperature Discuss
Materials and Components problems
Search Results
Correct Answer: temporary smagnets
Correct Answer: mutual inductance
Explanation:
A high voltage is induced due to mutual inductance because the number of turns in secondary coil is very high.
Correct Answer: True
Correct Answer: True
Correct Answer: 1.672 x 10-26 kg and 9.107 x 10-31 kg respectively
Correct Answer: 0.01
Correct Answer: False
Explanation:
Lines of magnetic field repel each other.
Correct Answer: decreases
Correct Answer: True
Correct Answer: Transition temperature
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