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  • Question

  • Assertion (A): In imperfect capacitors, the current does not lead the applied ac voltage by 90°.

    Reason (R): When subjected to ac fields, the dielectric constant can be expressed as ?'r - j?"r.


  • 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 

    Explanation
    Imaginary part of ?r gives rise to absorption of energy by the material from alternating field.

    Hence current does not lead the voltage by 90°.

    Materials and Components problems

    Search Results

    • 1. The number of valence electrons in donor impurity are

    • Options
    • A. 5
    • B. 4
    • C. 3
    • D. 1
      • Discuss
    • 2. When an electric field E is applied to solid and liquid insulating materials, the internal field Ei acting at the location of atom is such that

    • Options
    • A. Ei = E
    • B. Ei > E
    • C. Ei < E
    • D. Ei may be equal to or less than E
      • Discuss
    • 3. Assertion (A): Power loss in a conductor of resistance P = I2R.

      Reason (R): When a conductor is carrying current with current density J as a result of applied field E, then heat developed/m3/ second = JE.


    • 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
    • 4. Which of the following are donor impurities?

      1. Gold
      2. Phosphorus
      3. Boron
      4. Antimony
      5. Arsenic
      6. Induim
      Select the correct answer using the following codes

    • Options
    • A. 1, 2, 3
    • B. 1, 2, 4, 6
    • C. 3, 4, 5, 6
    • D. 2, 4, 5
      • Discuss
    • 5. Assertion (A): Atomic number of sodium is 11.

      Reason (R): Sodium has a body centred cubic lattice.


    • 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
    • 6. Assertion (A): Ferroelectric materials have spontaneous polarization.

      Reason (R): Above curie temperature, ? = for ferro-electric materials.


    • 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. Which capacitor-store higher amount of energy?

    • Options
    • A. Air capacitor
    • B. Paper capacitor
    • C. Mica capacitor
    • D. Plastic film capacitor
      • Discuss
    • 8. If the temperature of an extrinsic semiconductor is increased so that the intrinsic carrier concentration is doubled, then

    • Options
    • A. the majority carrier density is doubled
    • B. the minority carrier density is doubled
    • C. the minority carrier density becomes 4 times the original value
    • D. both the majority and minority carrier densities double
      • Discuss
    • 9. Assertion (A): Magnetic susceptibility of diamagnetic materials is much less than that of paramagnetic materials.

      Reason (R): For diamagnetic as well as paramagnetic materials, ?r is nearly equal to 1.


    • 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. Which element exhibits the property of inertia?

    • Options
    • A. Resistance
    • B. Capacitance
    • C. Inductance
    • D. Both resistance and inductance
      • Discuss

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