logo

CuriousTab

CuriousTab

Discussion

Home ‣ Electronics and Communication Engineering ‣ Exam Questions Papers See What Others Are Saying!
  • Question

  • The specific gravity of tungsten is 13.8 and its atomic weight is 184.0 Assume that there are two free elements per atom. Then the Fermi level or characteristic energy for the crystal in eV will be


  • Options
  • A. 8.95 eV
  • B. -8.95 eV
  • C. 7.326 eV
  • D. -7.326 eV

  • Correct Answer
  • 7.326 eV 

    Explanation
    A quantity of any substance equal to its molecular weight in grams is a mole of that substance contains the same number of molecules as one mole of any other substance. This Avogadro's number and equals 6.02 x 1023 molecules per mole. Thus

    The specific gravity of tungsten is 13.8 and its atomic weight is 184.0 Assume that there are two fr

    The specific gravity of tungsten is 13.8 and its atomic weight is 184.0 Assume that there are two fr

    The specific gravity of tungsten is 13.8 and its atomic weight is 184.0 Assume that there are two fr

    = 9.03 x 1028 electrons/m3

    Since for tungsten the atomic and the molecular weights are the same. Therefore for tungsten

    EF = 3.64 x 10-19(?)2/3

    = 3.64 x 10- 19(9.03 x 1028)2/3

    EF = 7.326 eV.

    More questions

    • 1. The output frequency of a cycloconverter can be changed by changing the firing angle.

    • Options
    • A. True
    • B. False
      • Discuss
    • 2. Most of the memory chips in static RAM

    • Options
    • A. do not require any supply
    • B. need 2 V supply
    • C. need 5 V supply
    • D. need 12 V supply
      • Discuss
    • 3. In crystalline solids, atoms are stacked in a regular manner.

    • Options
    • A. True
    • B. False
      • Discuss
    • 4. The classes of solid dielectrics are

    • Options
    • A. A, B, C, D, E, F, H
    • B. A E B F H C D
    • C. Y A E B F H C
    • D. A E B F H C
      • Discuss
    • 5. The unit for mmf is

    • Options
    • A. A
    • B. Wb
    • C. T
    • D. V
      • Discuss
    • 6. In a single phase full wave regulator, the firing angles in the positive and negative half cycles are generally

    • Options
    • A. equal
    • B. different
    • C. equal or different
    • D. different but sometimes equal
      • Discuss
    • 7. The real part of complex dielectric constant and tan? for a dielectric are 2.1 and 5 x 10-4 at 100 Hz respectively. The imaginary part of dielectric constant at 100 Hz is

    • Options
    • A. 1.05 x 10-3
    • B. 2.1 x 10-3
    • C. 5 x 10-3
    • D. 1.05 x 10-2
      • Discuss
    • 8. The units for ?r are

    • Options
    • A. Farads
    • B. Farads/m
    • C.
    • D. no units
      • Discuss
    • 9. Tesla is a unit of

    • Options
    • A. flux
    • B. field strength
    • C. flux density
    • D. MMF
      • Discuss
    • 10. In a receiver, which of the following device has IF input but RF output?

    • Options
    • A. Demodulator
    • B. Loudspeaker
    • C. Audio amplifier
    • D. Frequency changer
      • Discuss

    Comments

    There are no comments.
Enter a new Comment




Aptitude

Engineering

Programming

Reasoning

Links

Copyright ©CuriousTab. All rights reserved.