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  • Question

  • A liquid has N permanent dipoles ?p per unit volume and has been subjected to dc field for a long time such that orientation polarization is P0. At t = 0, the field is suddenly removed, then polarization


  • Options
  • A. will remain constant at P0
  • B. will become zero at t = 0
  • C. will delay to zero with a time constant
  • D. either b or c

  • Correct Answer
  • will delay to zero with a time constant 

    • Materials and Components problems

    Search Results

    • 1. Assertion (A): Ferromagnetic materials possess ferromagnetic properties only when temperature is less than paramagnetic curie temperature.

      Reason (R): For a ferromagnetic material for T > ?f.


    • 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. In carbon resistor colour code, if the third band is of silver, it indicates

    • Options
    • A. that three zeros are to be added to indicate the resistance value
    • B. multiplier is 0.01
    • C. multiplier is 0.1
    • D. tolerance is ± 5%
      • Discuss
    • 3. To produce magnetic flux, mmf is necessary.

    • Options
    • A. True
    • B. False
      • Discuss
    • 4. The orientation polarization is

      1. directly proportional to temperature
      2. inversely proportional to temperature
      3. inversely proportional to square of permanent dipole moment
      4. directly proportional to square of permanent dipole moment.
      Which of the above are correct?

    • Options
    • A. 1 and 3 only
    • B. 2 and 3 only
    • C. 1 and 4 only
    • D. 2 and 4 only
      • Discuss
    • 5. The colour code on a carbon resistor is red-red-black-silver. The value of resistor is

    • Options
    • A. 22000 ?
    • B. 2200 ?
    • C. 22 ± 5% ?
    • D. 22 ± 10% ?
      • Discuss
    • 6. The temperature coefficient of a thermistor

    • Options
    • A. is positive
    • B. is negative
    • C. zero
    • D. may be positive or negative depending on its composition
      • Discuss
    • 7. In a rare gas, the molecules of some atoms have an excess positive or negative charge. The electric field tends to shift positive ions relative to negative ions. This is known as ionic polarization.

    • Options
    • A. True
    • B. False
      • Discuss
    • 8. As per Bohr's postulate, only those circular orbits are stable for which the angular momentum is equal to an integer times .

    • Options
    • A. True
    • B. False
      • Discuss
    • 9. Nichrome is used for

    • Options
    • A. overhead line wires
    • B. heater coils
    • C. lamp filaments
    • D. all of the above
      • Discuss
    • 10. In a specimen of silicon steel, a field strength of 200 A/m causes a flux density of 0.5 T. In a specimen of cast iron, the same H would cause B to be

    • Options
    • A. 0.5 T
    • B. less than 0.5 T
    • C. more than 0.5 T
    • D. 0.5 T or more or less
      • Discuss

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