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ECE :: Materials and Components

  1. Diamond is a paramagnetic material.

  2. A.
    True
    B.
    False

  3. Which capacitor-store higher amount of energy?

  4. A.
    Air capacitor
    B.
    Paper capacitor
    C.
    Mica capacitor
    D.
    Plastic film capacitor

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

  6. A.
    True
    B.
    False

  7. In paramagnetic materials

  8. 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

  9. Assertion (A): Atomic number of sodium is 11.

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

  10. 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

  11. The conductivity of intrinsic semiconductor is given by

  12. A.
    enip - μn)
    B.
    enip + μn)
    C.
    nip + μn)
    D.
    nipμn)

  13. 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

  14. A.
    32 mH
    B.
    16 mH
    C.
    8 mH
    D.
    4 mH

  15. The minority carrier life time and diffusion constant in a semiconducting material are 100 μs and 100 cm2/s respectively. The diffusion length of carriers is

  16. A.
    0.1 cm
    B.
    0.01 cm
    C.
    0.0141 cm
    D.
    1 cm

  17. Assertion (A): Electronic and Ionic polarization in a polyatomic gas are independent of temperature.

    Reason (R): The orientation polarization is independent of temperature.

  18. 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

  19. Two materials having temperature coefficients of 0.004 and 0.0004 respectively are joined in series. The overall temperature coefficient is likely to be

  20. A.
    0.08
    B.
    0.04
    C.
    0.001
    D.
    0.0001