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Mechanical Engineering :: Thermodynamics

  1. The general gas equation is (where p = Pressure, v = Volume, m = mass, T = Absolute temperature, and R = Gas constant)

  2. A.

     pv = mRT

    B.

     pv = RTm

    C.

     pvm = C

    D.

     pv = (RT)m


  3. The heat supplied to the gas at constant volume is (where m = Mass of gas, cv = Specific heat at constant volume, cp = Specific heat at constant pressure, T2 - T1 = Rise in temperature, and R = Gas constant)

  4. A.

     mR (T2 - T1)

    B.

     mcv (T2 - T1)

    C.

     mcp (T2 - T1)

    D.

     mcp (T2 + T1)


  5. Relation between cp and cv is given by (where cp = Specific heat at constant pressure, cv = Specific heat at constant volume, γ = cp/cv, known as adiabatic index, and R = Gas constant)

  6. A.

     cv/ cp =R

    B.

     cp - cv = R

    C.

     cv = R/ γ-1

    D.

     Both (B) and (C)


  7. Those substances which have so far not been resolved by any means into other substances of simpler form are called

  8. A.

     Atoms

    B.

     Compounds

    C.

     Elements

    D.

     Molecules


  9. For same compression ratio and for same heat added

  10. A.

     Otto cycle is more efficient than Diesel cycle

    B.

     Diesel cycle is more efficient than Otto cycle

    C.

     Efficiency depends on other factors

    D.

     Both Otto and Diesel cycles are equally efficient


  11. The natural solid fuel is

  12. A.

     Wood

    B.

     Coke

    C.

     Pulverised coal

    D.

     Anthracite coal


  13. The heat absorbed or rejected by the working substance is given by (where ds = Increase or decrease of entropy, T = Absolute temperature, and dQ = Heat absorbed or rejected)

  14. A.

     δQ = T.ds

    B.

     δQ = T/ds

    C.

     dQ = ds/T

    D.

     None of these


  15. The efficiency of a gas turbine is given by

  16. A.

     (Net work output)/(Work-done by the turbine)

    B.

     (Net work output)/(Heat supplied)

    C.

     (Actual temperature drop)/(Isentropic temperature drop)

    D.

     (Isentropic increase in temperature)/(Actual increase in temperature)


  17. One kg of carbon monoxide requires __________ kg of oxygen to produce 11/7 kg of carbon dioxide gas.

  18. A.

     4/7

    B.

     11/4

    C.

     9/7

    D.

     All of these


  19. One kg of carbon monoxide requires _________kg of oxygen to produce 11/7 kg of carbon dioxide gas.

  20. A.

     11/7

    B.

     9/7

    C.

     4/7

    D.

     All of the above