SECTION-1

THERMODYNAMIC OBJECTIVE QUESTIONS/MCQ

Q71. The process is adiabatic, if the value of n in the equation pvn=C, is

(a) 0

(b) 1

(c) γ

(d) ∞

Ans (c) γ

Q72. If in the equation pvn =C, the value of n=∞, then the process is called

(a) constant volume process

(c) constant pressure process

(d) isothermal process

Ans  (a) constant volume process

Q73. In an irreversible process, there is a

(a) loss of heat

(b) no loss of heat

(c) gain of heat

(d) no gain of heat

Ans (a) loss of heat

Q74. Reversed Joule cycle is known as

(a) Carnot cycle

(b) Bell-Coleman cycle

(c) Rankine cycle

(d) Stirling cycle

Ans: (b) Bell-Coleman cycle

Q75. A cycle consisting of one constant pressure, one constant volume and two isentropic processes is known as

(a) Carnot cycle

(b) Stirling cycle

(c) Otto cycle

(d) Diesel cycle

Ans (d) Diesel cycle

Q76. Which of the following is the correct statement?

(a) For a given compression ratio, both Otto and Diesel cycles have the same efficiency

(b) Fora given compression ratio, Otto cycle is more efficient than Diesel cycle.

(c) For a given compression ratio, Diesel cycle is more efficient than Otto cycle.

(d) The efficiency of Otto or Diesel cycle has nothing to do with compression ratio.

Ans (b) For a given compression ratio, Otto cycle is more efficient than Diesel cycle.

Q77. Which of the following is the correct statement?

(a) All the reversible engines have the same efficiency.

(b) All the reversible and irreversible engines have the same efficiency.

(c) Irreversible engines have maximum efficiency

(d) All engines are designed as reversible in order to obtain maximum efficiency.

Ans (c) Irreversible engines have maximum efficiency

Q78. When cut-off ratio is………. the efficiency of Diesel cycle approaches to Otto cycle efficiency.

(a) zero

(b) 1/5

(c) 4/5

(d) 1

Ans (a) zero

Q79. The efficiency of the dual combustion cycle for the same compression ratio, is………Diesel cycle.

(a) greater than

(b) less than

(c) equal to

(d) none pf these

Ans (a) greater than

Q80. When the expansion or compression takes place according to the law pvn= C, the process is known as

(a) isothermal process

(c) hyperbolic process

(d) polytropic process

Ans (d) polytropic process

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##### Read More Sections of Thermodynamics Objective Questions

Each section contains maximum 80 Questions. To practice more questions visit other sections.

Thermodynamics Objective Questions – Section-1

Thermodynamics Objective Questions – Section-2

Thermodynamics Objective Questions – Section-3

Thermodynamics Objective Questions – Section-4