Discussion
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- Question
Assertion (A): In a parallel plate capacitor having area of plate 1 m2 and plate separation 1 m, the capacitance C and resistance R are given by C = ?0?'r and R =
where ? is frequency, ?r' and ?r" are real and imaginary parts of dielectric constant.Reason (R): The imaginary part of electric constant is responsible for dielectric losses.
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
- Correct Answer
- Both A and R are true and R is correct explanation of A
- 1. In intrinsic semiconductors, the number of free electrons is equal to the number of mobile holes.
Options- A. True
- B. False Discuss
- 2. In a pure sample of silicon
Options- A. the number of holes and free electrons is always equal
- B. the number of free electrons is more than the number of holes
- C. the number of free electrons and holes is equal at low temperature
- D. the number of free electrons is less than number of holes Discuss
- 3. Which of the following is the poorest conductor of electricity?
Options- A. Aluminium
- B. Nichrome
- C. Copper
- D. All of the above Discuss
- 4. A permeable substance is one
Options- A. which is strong magnet
- B. which is a weak magnet
- C. which is a good conductor
- D. through which magnetic lines of force can pass easily Discuss
- 5. Ferrites have
Options- A. a low copper loss
- B. low eddy current loss
- C. low resistivity
- D. higher specific gravity compared to iron Discuss
- 6. Assertion (A): When an electron is revolving in its orbit and magnetic field is also present, the angular frequency of electron will be affected by the magnetic field.
Reason (R): In the case of electron revolving in its orbit in the presence of magnetic field, the orbital magnetic dipole moment is not affected by the presence of magnetic field.
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. When subjected to alternating stresses, an insulating material is characterised by complex dielectric constant ?'r - j?"r . In such materials, the dielectric losses under alternating stress is proportional
Options- A. ?"r
- B. both ?'r and ?"r
- C. ?'r
- D. (?"r)2 Discuss
- 8. Assertion (A): Relaxation time and mean time between collisions are equal when scattering is isotropic.
Reason (R): Mean free path of an electron ?, velocity of electron v and mean time between collisions tc are related as ? = vTc.
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. Assertion (A): CO2 has no resultant dipole moment but CO has a dipole moment.
Reason (R): The structure of CO2 is O = C = O.
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
- 10. Paramagnetic materials have permanent magnetic dipoles but interaction between neighbouring dipoles is negligible.
Options- A. True
- B. False Discuss
Materials and Components problems
Search Results
Correct Answer: True
Correct Answer: the number of holes and free electrons is always equal
Correct Answer: Nichrome
Correct Answer: through which magnetic lines of force can pass easily
Correct Answer: low eddy current loss
Explanation:
Resistivity of ferrites is very high as compared to that of iron. Hence eddy curretns are much less.
Correct Answer: A is true but R is false
Explanation:
Orbital magnetic moment is equal to (-e/2m).
Correct Answer: ?"r
Explanation:
The imaginary part of ?r gives rise to absorption of energy.
Correct Answer: Both A and R are true but R is not correct explanation of A
Correct Answer: Both A and R are true and R is correct explanation of A
Correct Answer: True
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