With increase in compression ratio, the efficiency of the otto engine________________?

Related Mcqs:

1. The efficiency of an Otto engine compared to that of a diesel engine, for the same compression ratio will be _______________?

   A. More
   B. Less
   C. Same
   D. Data insufficient to predict

2. The work done in isothermal compression compared to that in adiabatic compression will be__________________?

   A. Less
   B. More
   C. Same
   D. More or less depending upon the extent of work done

3. Air enters an adiabatic compressor at 300K. The exit temperature for a compression ratio of 3, assuming air to be an ideal gas (Y = Cp/Cv = 7/5) and the process to be reversible, is___________________?

   A. 300 × (32/7)
   B. 300 × (33/5)
   C. 300 × (333/7)
   D. 300 × (35/7)

4. Major sources of noise in furnace operation arises from air inspirators, combustion, side wall vibrations and fluctuation in the process heat load. A 50% increase in fuel firing rate may increase the furnace noise level by about ____________ decibels?

   A. 3
   B. 30
   C. 7
   D. 70

5. The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition?

   A. Internal energy
   B. Enthalpy
   C. Gibbs free energy
   D. Helmholtz free energy

6. What happens in a reversible adiabatic compression ?

   A. Heating occurs
   B. Cooling occurs
   C. Pressure is constant
   D. Temperature is constant

7. In case of vapour compression refrigeration system, elevating the evaporator temperature (keeping the condenser temperature constant) results in_____________?

   A. Enhanced COP
   B. Decreased COP
   C. No change in the value of COP
   D. Increased or decreased COP; depending upon the type of refrigerant

8. Adiabatic compression of a saturated water vapour makes it ____________________ ?

   A. Supersaturated
   B. Superheated
   C. Both A. and B
   D. Neither A. nor B

9. In case of steady flow compression polytropic process (PVn = constant), the work done on air is the lowest, when_______________?

   A. n = y = 1.4
   B. n = 0
   C. n = 1
   D. n = 1.66

10. Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in__________________?

    A. Increased COP
    B. Same COP
    C. Decreased COP
    D. Increased or decreased COP; depending upon the type of refrigerant