Home / ECE / Materials and Components :: Section 4

ECE :: Materials and Components

  1. Assertion (A): Diamond and carborudum are both very hard materials.

    Reason (R): Valence band can be extremely strong.

  2. 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

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  3. The chemical properties of atoms are determined by all the electrons and their configuration.

  4. A.
    True
    B.
    False

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  5. Nichrome is used for

  6. A.
    overload line wires
    B.
    heater coils
    C.
    lamp filaments
    D.
    all of the above

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  7. If k is Boltzmann's constant and T is absolute temp, then at room temp.

  8. A.
    kT 0.025 eV
    B.
    kT 0.5 eV
    C.
    kT 1 eV
    D.
    kT 100 eV

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  9. The dielectrics having only one kind of atoms are known as elemental dielectrics.

  10. A.
    True
    B.
    False

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  11. For a core having a relative permeability μr, magnetic dipole moment per unit volume M and field strength H, the flux density B is

  12. A.
    B = μr (H + M)
    B.
    B = μ0 (H + M)
    C.
    B = μ0μr (H + M)
    D.
    B = μ0μr (H - M)

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  13. The law that (where K is thermal conductivity, σ is electrical conductivity and T is absolute temperature) for all metals is equal to a universal constant is known as

  14. A.
    Lorentz law
    B.
    Wiedemann Franz law
    C.
    Curie Weiss law
    D.
    Kittel law

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  15. In elemental dielectrics, the orientation and ionic polarization are absent.

  16. A.
    True
    B.
    False

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  17. In which of the following semiconductor are holes majority carriers

  18. A.
    intrinsic
    B.
    extrinsic
    C.
    p type
    D.
    n type

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  19. The equation D = ∈0r E refers only to isotropic materials.

  20. A.
    True
    B.
    False

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