CARNOT CYCLE MULTIPLE CHOICE QUESTIONS (MCQ) WITH ANSWERS

CARNOT CYCLE MULTIPLE

CHOICE QUESTIONS

(MCQ) WITH ANSWERS 

MCQ help in better understanding.

Carnot Cycle is a most efficient power

producing cycle. It has two isentropic and

two isothermal processes. In the Carnot

Cycle, equations are there for the change

of entropy in a process. Every process in

nature is irreversible. Entropy increases

due to irreversibility. Increase of entropy is

undesirable as it reduces availability.

  1. Entropy of a refrigerant is zero in S.I. units at a temperature of

  1. 00C

  2. -400C

  3. +1000C

  4. None

Ans: (ii)

  1. Change of entropy during heating at constant pressure is equal to

  1. Cvln(T2/T1)

  2. (1+Cp) ln(V2/V1)

  3. Cpln(T2/T1)+ Cpln(V2/V1)

  4. None

Ans: (i)

  1. Under iso-thermal conditions, change of entropy from p1 to p2  will be

  1. Firstly Cp ln(p2/p1)

  2. Secondly Cv  ln(V2/V1) 

  3. Thirdly Cpln(p2/p1) + Cpln(V2/V1)

  4. None

Ans: (i)

  1. When is the change of entropy is zero under an

  1. Constant temperature process

  2. Iso – choric process

  3. Constant pressure process

  4. None

Ans: (iv)

  1. No change of entropy during a

  1. Adiabatic process

  2. Constant enthalpy process

  3. Constant internal energy process

  4. None

Ans: (iv)

  1. During heating at constant volume process, change of specific entropy  is

  1. Cv ln (p2/p1)

  2. Cp ln (p2/p1)

  3. Cp ln (T2/T1)

  4. None

Ans: (iv)

  1. In an iso-thermal process, change of entropy  will be

  1. Cp ln (v2/v1)

  2. Cv ln (v2/v1)

  3. R ln (v2/v1)

  4. None

Ans: (iii )

  1. General expression for the change of entropy is

  1. R ln (v2/v1) + Cp ln(T2/T1)

  2. R ln (v2/v1) + Cv ln(T2/T1)

  3. Cp ln (v2/v1) + Cp ln(T2/T1)

  4. None

Ans: (ii)

  1. An adiabatic process will have change of entropy as

  1. ((n—γ)/(n—1)) ln(T2/T1)

  2. Cp ((n—γ)/(n—1)) ln(T2/T1)

  3. Cv ((n—γ)/(n—1)) ln(T2/T1)

  4. None

Ans: (iii)

  1.  Reversible adiabatic process will have change of entropy as

  1. Cv ((n—γ)/(n—1)) ln(T2/T1)

  2. Cp ((n—γ)/(n—1)) ln(T2/T1)

  3. ((n—γ)/(n—1)) ln(T2/T1)

  4. None

Ans: (iv)

  1. During an irreversible process, there is

  1. Increase of entropy

  2. Decrease of entropy

  3. No change in entropy

  4. None

Ans: (i)

  1. Increase of entropy is

  1. Good

  2. Neither good nor bad

  3. Bad

  4. None

Ans: (iii)

  1. Decrease of entropy is in case of

  1.  Pressure decrease

  2. Decrease in volume

  3. Both decrease in pressure & volume

  4. None

Ans: (ii)

  1. Entropy increases with the

  1. Addition of heat

  2. Removal of heat

  3. At constant heat

  4. None

Ans:(i)

  1. Under what conditions, entropy becomes double when

  1. Temperature is doubled

  2. Pressure  becomes double

  3. Volume is doubled

  4. None

Ans: (iv)

  1. A Carnot cycle is a

  1. real cycle

  2. Ideal cycle

  3. Experimentally verified cycle

  4. None

Ans: (b)

  1. On a temperature entropy chart, Carnot cycle will be a

  1. Rhombus

  2. Rectangle

  3. Triangle

  4. None

Ans: (ii)

  1. The order of processes in a Carnot Cycle is

  1. Isothermal—isothermal—isentropic—isentropic

  2. isentropic—isothermal–—isothermal-isentropic

  3. Isothermal—isentropic——isothermal –isentropic

  4. None

Ans: (c)

  1. Over the complete Carnot Cycle, entropy

  1. increases

  2. Decreases

  3. No change

  4. None

Ans:(iii)

  1. With the rise of temperature in a system, sum of entropy of a system and its surroundings

  1. Increases

  2. Decreases

  3. Remains constant

  4. None

Ans: (iii)

  1. While there is rise of pressure in a system, sum of entropy of a system and its surroundings

  1. Increases

  2. Decreases

  3. Remains constant

  4. None

Ans: (iii)

  1. A petrol engine assumed to work on Carnot Cycle. It works between temperatures of 12000C and 2000 .The efficiency of the engine will be

  1. 99 %

  2. 79 %

  3. 69 %

  4. None

Ans: (iii)

  1. Work done will be maximum using pvn=Constant when the value of index ‘n’ will be

  1. 1

  2. 4

  3. 3

  4. None

Ans: (ii)

  1. Minimum Work will be done  using pvn=Constant when the value of index ‘n’ will be

  1. 1

  2. 4

  3. 3

  4. None

Ans: (i)

  1. Compression ratio in a diesel cycle/petrol cycle is approximately equal to

  1. 25

  2. 5

  3. 15

  4. None

Ans: (ii)

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