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  • Question
  • Assertion (A): For Diamond, ?r = 1

    Reason (R): Diamond is a diamagnetic material.


  • 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
    For diamagnetic materials ?r = 1.

    Materials and Components problems


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    • 1. If a piece of wood is placed in a magnetic field

    • Options
    • A. the magnetic field will not be affected
    • B. the magnetic lines of force will bend towards the piece
    • C. the magnetic lines of force will bend away from the piece
    • D. the flux may increase or decrease
    • Discuss
    • 2. For a paramagnetic material, susceptiblity increases with increasing temperature.

    • Options
    • A. True
    • B. False
    • Discuss
    • 3. If a sample of germanium and a sample of silicon have the same impurity density and are kept at room temperature

    • Options
    • A. both will have equal value of resistivity
    • B. both will have equal negative resistivity
    • C. resistivity of germanium will be higher than that of silicon
    • D. resistivity of silicon will be higher than that of germanium
    • Discuss
    • 4. The minority carrier life time and diffusion constant in a semiconducting material are 100 ?s and 100 cm2/s respectively. The diffusion length of carriers is

    • Options
    • A. 0.1 cm
    • B. 0.01 cm
    • C. 0.0141 cm
    • D. 1 cm
    • Discuss
    • 5. The attraction between the nucleus and valence electron of copper atom is

    • Options
    • A. zero
    • B. weak
    • C. strong
    • D. either zero or strong
    • Discuss
    • 6. In metals the valence electron wave functions are strongly perturbed by the presence of neighbouring atoms.

    • Options
    • A. True
    • B. False
    • Discuss
    • 7. The core of a coil has a length of 10 cm. The self inductance is 8 mH. If the core length is doubled, all other quantities remaining the same, the self inductance will be

    • Options
    • A. 32 mH
    • B. 16 mH
    • C. 8 mH
    • D. 4 mH
    • Discuss
    • 8. Assertion (A): For a solenoid having N turns, .

      Reason (R): For all magnetic materials, B increases linearly with I.


    • 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. The law J = ?E, where J is current density, ? is electrical conductivity and E is field strength is

    • Options
    • A. Ohm's law
    • B. Gauss law
    • C. Ampere's law
    • D. Biot-Savart law
    • Discuss
    • 10. If ?r' and ?r" are the real and imaginary parts of complex dielectric constant ?r, and ? is the loss angle. Then

    • Options
    • A.
    • B.
    • C. tan ? = ?'?"
    • D. tan ? = 1 - ?'
    • Discuss


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