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  • Question

  • Above ferroelectric curie temperature, spontaneous polarization in ferroelectric materials becomes stronger.


  • Options
  • A. True
  • B. False

  • Correct Answer
  • False 

    Explanation
    Spontaneous polarization vanishes above ferro-electric Curie temperature.

    More questions

    • 1. To cover all inhabited regions of the Earth, the number of geosynchronous communication satellites required

    • Options
    • A. 5
    • B. 3
    • C. 10
    • D. 2
      • Discuss
    • 2. In an n-p-n transistor biased for operation in forward active region

    • Options
    • A. emitter is positive with respect to base
    • B. collector is positive with respect to base
    • C. base is positive with respect to emitter and collector is positive with respect to base
    • D. none of the above
      • Discuss
    • 3. Consider the following applications

      1. Switch
      2. Attenuator
      3. Phase shifter
      4. Oscillator
      In which of the above can a PIN diode be used?

    • Options
    • A. 1 2 3 and 4
    • B. 1 2 and 3 only
    • C. 1 and 2 only
    • D. 2, 3 and 4 only
      • Discuss
    • 4. The frequency of oscillation in a backward wave oscillator can be changed by

    • Options
    • A. varying the voltage which controls beam velocity
    • B. varying the beam current
    • C. both by varying the beam current and by light varying the voltage which controls beam velocity
    • D. changing the rate of thermionic emission
      • Discuss
    • 5. Two networks are cascaded through an ideal buffer. If td1 and td2 are delay times of network, the overall delay time is

    • Options
    • A. td1 + td2
    • B. t2d1 + t2d2
    • C. td1 + td2
    • D.
      • Discuss
    • 6. In paramagnetic materials

    • Options
    • A. permanent magnetic dipoles exist but the interaction between neighbouring dipoles is negligible
    • B. permanent magnetic dipole do not exist
    • C. permanent magnetic dipoles exist and the interaction between neighbouring dipoles is very strong
    • D. permanent magnetic dipole moment may or may not exist
      • Discuss
    • 7. In a microwave coaxial line, the maximum operating frequency is f max and breakdown strength of dielectric is Ed' Then maximum power handling capacity is proportional to

    • Options
    • A.
    • B.
    • C.
    • D.
      • Discuss
    • 8. If m, v, r are the mass, velocity and radius of orbit of electron and h is Planck's constant, quantum condition for electron's orbit is

    • Options
    • A.
    • B.
    • C.
    • D.
      • Discuss
    • 9. Which chopper circuit operates in all the 4 quadrants?

    • Options
    • A. A
    • B. C
    • C. D
    • D. E
      • Discuss
    • 10. If r is resistivity, l is length of wire, a is area of cross-section, ? is angular frequency, F is form factor, n is number of turns, d is coil diameter and r is resistance of a coil.

      List I List II
      A. Value of inductance 1.
      B. Power factor 2.
      C. Q factor 3.
      D. Value of resistance 4. Fn2d


    • Options
    • A. A-1, B-2, C-3, D-4
    • B. A-4, B-3, C-2, D-1
    • C. A-4, B-2, C-3, D-1
    • D. A-1, B-3, C-2, D-4
      • Discuss

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