Mechanical Engineering Thermodynamics - Set 09 - ObjectiveBooks

Mechanical Engineering Thermodynamics - Set 09

Practice Test: Question Set - 09

1. Carnot cycle efficiency is maximum when
    (A) Initial temperature is 0°K
    (B) Final temperature is 0°K
    (C) Difference between initial and final temperature is 0°K
    (D) Final temperature is 0°C

2. If heat be exchanged in a reversible manner, which of the following property of the working substance will change accordingly
    (A) Temperature
    (B) Enthalpy
    (C) Internal energy
    (D) Entropy

3. The area under the temperature-entropy curve (Ts curve) of any thermodynamic process represents
    (A) Heat absorbed
    (B) Heat rejected
    (C) Either heat absorbed or heat rejected
    (D) None of these

4. One kg of carbon produces ________ kg of carbon dioxide.
    (A) 3/7
    (B) 11/7
    (C) 11/3
    (D) 4/11

5. If a system after undergoing a series of processes, returns to the initial state then
    (A) Process is thermodynamically in equilibrium
    (B) Process is executed in closed system cycle
    (C) Its entropy will change due to irreversibility
    (D) Sum of heat and work transfer will be zero

6. An actual engine is to be designed having same efficiency as the Carnot cycle. Such a proposition is
    (A) Feasible
    (B) Impossible
    (C) Possible
    (D) Possible, but with lot of sophistications

7. A manufacturer claims to have a heat engine capable of developing 20 h.p. by receiving heat input of 400 kcal/mt and working between the temperature limits of 227° C and 27° C. His claim is
    (A) Theoretically possible
    (B) Not possible
    (C) May be possible with lot of sophistications
    (D) Cost will be very high

8. Which of the following is the correct statement of the second law of thermodynamics?
    (A) There is a definite amount of mechanical energy, which can be obtained from a given quantity of heat energy
    (B) It is impossible to transfer heat from a body at a lower temperature to a higher temperature, without the aid of an external source
    (C) It is impossible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work
    (D) All of the above

9. A mixture of gas expands from 0.03 m3 to 0.06 m3 at a constant pressure of 1 MPa and absorbs 84 kJ of heat during the process. The change in internal energy of the mixture is
    (A) 30 kJ
    (B) 84 kJ
    (C) 54 kJ
    (D) 114 kJ

10. In a Carnot cycle, heat is transferred at
    (A) Constant pressure
    (B) Constant volume
    (C) Constant temperature
    (D) Constant enthalpy

11. A diathermic wall is one which
    (A) Prevents thermal interaction
    (B) Permits thermal interaction
    (C) Encourages thermal interaction
    (D) Discourages thermal interaction

12. An adiabatic wall is one which
    (A) Prevents thermal interaction
    (B) Permits thermal interaction
    (C) Encourages thermal interaction
    (D) Discourages thermal interaction

13. Producer gas is obtained by
    (A) Carbonization of bituminous coal
    (B) Partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast
    (C) Passing steam over incandescent coke
    (D) Passing air and a large amount of steam over waste coal at about 650°C

14. The efficiency of Diesel cycle depends upon
    (A) Pressure ratio
    (B) Cut-off ratio and compression ratio
    (C) Temperature limits
    (D) Compression ratio

15. The door of a running refrigerator inside a room was left open. Which of the following statements is correct?
    (A) The room will be cooled to the temperature inside the refrigerator
    (B) The room will be cooled very slightly
    (C) The room will be gradually warmed up
    (D) The temperature of the air in room will remain unaffected

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