# Multiple choice question for engineering

## Set 1

1. Energy out and Energy in of a system are 10 J and 25 J respectively, what is the efficiency of the system?

a) 10%

b) 40%

c) 50%

d) 80%

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2. Energy out and Energy in of a system are 5 J and 25 J respectively, what is the efficiency of the system?

a) 20%

b) 40%

c) 60%

d) 80%

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3. Energy out and Energy in of a system are 10 J and 20 J respectively, what is the efficiency of the system?

a) 20%

b) 30%

c) 40%

d) 50%

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4. Energy out and Energy in of a system are 40 J and 25 J respectively, what is the efficiency of the system?

a) 40%

b) 80%

c) 160%

d) 200%

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5. Energy out and Energy in of a system are 15 J and 25 J respectively, what is the efficiency of the system?

a) 40%

b) 60%

c) 80%

d) 110%

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6. What is the efficiency of the system, if the actual work output from the process is 10 J and work output for a reversible process is 40 J?

a) 10%

b) 25%

c) 40%

d) 65%

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7. What is the efficiency of the system, if the actual work output from the process is 20 J and work output for a reversible process is 25 J?

a) 10%

b) 20%

c) 40%

d) 80%

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8. What is the efficiency of the system, if the actual work output from the process is 15 J and work output for a reversible process is 20 J?

a) 25%

b) 50%

c) 75%

d) 100%

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9. What is the efficiency of the system, if the actual work input from the process is 10 J and work input for a reversible process is 20 J?

a) 20%

b) 50%

c) 100%

d) 200%

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10. What is the efficiency of the system, if the actual work input from the process is 20 J and work input for a reversible process is 25 J?

a) 20%

b) 80%

c) 125%

d) 150%

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11. What is the efficiency of a heat engine with heat input 10 J and work output 7 J?

a) 30%

b) 70%

c) 100%

d) 140%

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12. What is the efficiency of a heat engine with heat input 20 J and work output 5 J?

a) 25%

b) 50%

c) 75%

d) 100%

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13. What is the efficiency of a heat engine with heat input 5 J and work output 8 J?

a) 40%

b) 80%

c) 160%

d) 200%

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14. What is the coefficient of performance of a system, if its work input is 50 J and heat removed is 35 J?

a) 35%

b) 50%

c) 70%

d) 95%

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15. What is the coefficient of performance of a system, if its work input is 75 J and heat removed is 45 J?

a) 20%

b) 40%

c) 60%

d) 80%

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## Set 2

1. A reactor supplied with CO_{2} and H_{2}O, the product contains 10% H_{2}CO_{3} and 90% H_{2}O, what is the feed rate of CO_{2}, if the rate of product is 50 mole?

a) 5 mole

b) 10 mole

c) 25 mole

d) 50 mole

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_{2}+ H

_{2}O -> H

_{2}CO

_{3}. Let the rates of CO

_{2}and H

_{2}O be F and W respectively. Element balances, C: F(1) = 0.1P(1), => 10F = P, => F = 5 mole.

2. A reactor supplied with CO_{2} and H_{2}O, the product contains H_{2}O and H_{2}CO_{3}, if the rate of CO_{2} is 10 mole, what is the percentage of H_{2}CO_{3} in products?

a) 10

b) 50

c) 75

d) 100

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_{2}+ H

_{2}O -> H

_{2}CO

_{3}. Let the rate of CO

_{2}and H

_{2}O and product be F and W respectively, and the fraction of H

_{2}CO

_{3}in products be x. Element balances, C: F(1) = x*10(1), => F = 10x, => x = 1, => percentage of H

_{2}CO

_{3}= 100%.

3. A reactor supplied with CO_{2} and H_{2}O, the product contains H_{2}O and H_{2}CO_{3}, if the rate of H_{2}O is 10 mole, what is the rate of products?

a) 5 mole

b) 10 mole

c) 15 mole

d) 20 mole

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_{2}+ H

_{2}O -> H

_{2}CO

_{3}. Let the rate of products be P, and the fraction of H

_{2}CO

_{3}in products be x, material balances, H: 10(2) = x*P(2) + (1 – x)*P(2), => P = 10 mole.

4. A reactor supplied with CO_{2} and H_{2}O, the product contains CO_{2}, H_{2}O and H_{2}CO_{3}, if the rate of products is 10 mole and percentage of CO_{2} in products is 20%, what is the feed rate of H_{2}O?

a) 2 mole

b) 4 mole

c) 8 mole

d) 10 mole

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_{2}+ H

_{2}O -> H

_{2}CO

_{3}. Let the rate of H2O be W, and percentage of H

_{2}O in products be x. Material balances, H: W(2) = x*10(2) + (1 – x – 0.2)*10(2), => W = 8 mole.

5. A reactor supplied with CO_{2} and H_{2}O, the product contains 40% CO_{2}, 30% H_{2}O and 30% H_{2}CO_{3}, what is the ratio of feed rate of CO_{2} and rate of products?

a) 0.3

b) 0.4

c) 0.7

d) 0.9

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_{2}+ H

_{2}O -> H

_{2}CO

_{3}. Let the rate of CO

_{2}, H2O and H

_{2}CO

_{3}be F, W and P respectively. Element balances, C: F(1) = 0.4P(1) + 0.3P(1), => F/P = 0.7.

6. A reactor is supplied with Hexane and hydrogen to produce 20% methane, 30% propane and 50% butane, what is the ratio of hydrogen consumed and the hexane reacted?

a) 0.21

b) 0.45

c) 0.59

d) 0.73

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_{6}H

_{14}+ 2H

_{2}-> CH

_{4}+ 2C

_{3}H

_{8}+ C

_{5}H

_{12}, Let the rate of Hexane, hydrogen and products be F, W and P respectively. Element balances, C: 2F(6) = 0.2P(1) + 2*0.3P(3) + 0.5P(5), => 8F = 3P, H: 2F(14) + 2W(2) = 0.2P(4) + 2*0.3P(8) + 0.5P(12), => 7F + W = 2.9P, => W/F= 2.2/3 = 0.73.

7. A reactor is supplied with 10 mole of Hexane and some hydrogen to produce 20% methane, 30% propane and 50% butane, what is the rate of products?

a) 10 mole

b) 16.6 mole

c) 26.6 mole

d) 40 mole

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_{6}H

_{14}+ 2H

_{2}-> CH

_{4}+ 2C

_{3}H

_{8}+ C

_{5}H

_{12}, Let the rate of products be P. Element balance, C: 2*10(6) = 0.2P(1) + 2*0.3P(3) + 0.5P(5), => 120 = 4.5P, => P = 26.6 mole.

8. A reactor is supplied with glucose and oxygen to produce 40% CO_{2}, 60% H_{2}O, what is the ratio of glucose reacted and products?

a) 0.2

b) 0.4

c) 0.6

d) 0.8

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_{6}H

_{12}O

_{6}+ 6O

_{2}-> 6CO

_{2}+ 6H

_{2}O, Let the rate of glucose and products be F and P, Element balances, C: F(6) = 6*0.4P(1), => F/P = 0.4.

9. A reactor is supplied with 10 moles glucose and excess oxygen to produce 40% CO_{2}, 60% H_{2}O, what is the rate of products?

a) 25 mole

b) 50 mole

c) 75 mole

d) 100 mole

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_{6}H

_{12}O

_{6}+ 6O

_{2}-> 6CO

_{2}+ 6H

_{2}O, Let the rate of products be P. Element balances, C: 10(6) = 6*0.4P(1), => P = 25 mole.

10. A reactor is supplied with 10 moles glucose and excess oxygen to produce CO_{2} and H_{2}O, if the rate of products is 25 moles, what is the percentage of CO_{2} in the products?

a) 0.1

b) 0.2

c) 0.3

d) 0.4

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_{6}H

_{12}O

_{6}+ 6O

_{2}-> 6CO

_{2}+ 6H

_{2}O. Let the fraction of CO

_{2}be x, Element balances, C: 10(6) = 6*x*5(1), => x = 0.4.

11. Ethane is supplied at the rate F with oxygen at the rate W and leaves the following products CO_{2}, H_{2}O, O_{2}, C_{2}H_{6} and H_{2} at the rate P. How many independent element balances are possible?

a) 1

b) 2

c) 3

d) 4

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_{2}H

_{6}+ 3.5O

_{2}-> 2CO

_{2}+ 3H

_{2}O, since there are three elements C, H and O, we can write 3 independent material balances.

12. Ethane is supplied with chlorine in a reactor, how many independent element balances can you write?

a) 1

b) 2

c) 3

d) 4

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_{2}H

_{6}+ Cl

_{2}-> C

_{2}H

_{5}Cl + HCl, Element balance C: 2F = 2xP, H: 6F = 5xP + (1 – x)P, Cl: 2W = xP + (1 – x)P, => The equations are F = xP, 6F = 4xP + P, and 2W = P, which are independent.

13. A reactor is supplied with 2 streams both at same rates, one has pure Cl_{2}, and another has pure C_{2}H_{6}, if the product has 20% C_{2}H_{5}Cl and 80% HCl, what is the ratio of rate of feed and rate of product?

a) 0.2

b) 0.5

c) 2

d) 5

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_{2}H

_{6}+ Cl

_{2}-> C

_{2}H

_{5}Cl + HCl, Let the rate of feed and products be F and P respectively. Element balances, C: F(2) = 0.2P(2), => F/P = 0.2.

14. A reactor is supplied with 2 streams both at same rates, one has pure Cl_{2}, and another has pure C_{2}H_{6}, if the product has 20% C_{2}H_{5}Cl and 50% HCl and 30% C_{2}H_{6}, what is the ratio of rate of feed and rate of product?

a) 0.2

b) 0.5

c) 2

d) 5

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_{2}H

_{6}+ Cl

_{2}-> C

_{2}H

_{5}Cl + HCl, Let the rate of feed and products be F and P respectively. Element balances, C: F(2) – 0.3P(2) = 0.2P(2), => F/P = 0.5.

15. A reactor is supplied with 2 streams both at the rate 5 mole, one has 40% Cl_{2} and 60% N2, and another has pure C_{2}H_{6}, if the product has C_{2}H_{5}Cl, HCl and N_{2} at the rate 20 mole, what is the percentage of HCl in products?

a) 10%

b) 15%

c) 25%

d) 30%

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_{2}H

_{6}+ Cl

_{2}-> C

_{2}H

_{5}Cl + HCl, Let the fraction of C

_{2}H

_{5}Cl, HCl and N

_{2}be x, y and (1 – x – y) respectively. Element balances, Cl: 0.4*5(2) = x*10(1) + y*10(1), => x + y = 0.4, C: 5(2) = x*20(2), => x = 0.25, => y = 0.4 – 0.25 = 0.15, => percentage of HCl = 15%.

## Set 3

1. What separates system and surroundings?

a) Boundary

b) Temperature

c) Pressure

d) None of the mentioned

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2. Which of the following is true for open system?

a) Flow system

b) Non flow system

c) Cannot say

d) None of the mentioned

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3. Which of the following is true about closed system?

a) Flow system

b) Non flow system

c) Cannot say

d) None of the mentioned

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4. Which of the following does not change in steady state system?

a) Flow in rate

b) Flow out rate

c) Accumulation

d) None of the mentioned

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5. Which of the following is correct about an isothermal process?

a) ∆T = 0

b) dT = 0

c) ∆T /= 0

d) None of the mentioned

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6. Which of the following is a state function?

a) Work

b) Entropy

c) Heat

d) None of the mentioned

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7. Which of the following is a path function?

a) Work

b) Internal Energy

c) Entropy

d) None of the mentioned

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8. Internal energy is which of the following function?

a) Path function

b) State function

c) Cannot say

d) None of the mentioned

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9. Which of the following has steepest P-V curve?

a) Adiabatic

b) Isothermal

c) Isobaric

d) None of the mentioned

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10. What we call a process having constant volume throughout?

a) Isobaric

b) Isochoric

c) Isothermal

d) Adiabatic

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11. Which of the following is an extensive variable?

a) Pressure

b) Temperature

c) Volume

d) None of the mentioned

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12. Which of the following is an extensive variable?

a) Energy

b) Volume

c) Moles

d) All of the mentioned

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13. Which of the following is an intensive variable?

a) Moles

b) Enthalpy per mole

c) Enthalpy

d) All of the mentioned

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14. Which of the following is an intensive property?

a) Mole

b) Gibbs Free energy

c) Enthalpy

d) None of the mentioned

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15. Which of the following is an intensive property?

a) Refractive index

b) Hardness

c) Density

d) All of the mentioned

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## Set 4

1. Which of the following is not the type of energy?

a) Enthalpy

b) Heat

c) Entropy

d) Work

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2. Which of the following process P-V work in highest?

a) Second derivative is negative

b) Second derivative is positive

c) Second derivative is zero

d) All of the mentioned

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3. An object is moved from one position to another with a specific force, what type of work is it?

a) Shaft Work

b) Flow Work

c) Mechanical Work

d) None of the mentioned

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4. An object is moved at a distance of 10 m with the force of 5 N, what is the work done by the force?

a) 5 Joule

b) 50 Joule

c) 500 Joule

d) 5000 Joule

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5. An object moved forward 10 meters and then comes back 5 meter all with a constant force of 5 N, what is the work done by the force?

a) 5 Joule

b) 25 Joule

c) 50 Joule

d) 75 Joule

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6. A piston cylinder is compressed with some pressure, what is the work done on the system?

a) Positive

b) Negative

c) Zero

d) Cannot say

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7. A piston cylinder expands with some pressure, what is the work done by the system?

a) Positive

b) Negative

c) Zero

d) Cannot Say

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8. A piston cylinder contracts from 10 Liter to 5 Liter with and external pressure of 10 Pa, what is the work done on the system?

a) 0.5 mJ

b) 5 mJ

c) 10 mJ

d) 50 mJ

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9. A piston cylinder expands from 7 liter to 15 liter with external pressure of 500 Pa, what is the work done by the system?

a) – 1.5 Joule

b) – 4 Joule

c) 1.5 Joule

d) 4 Joule

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10. A piston cylinder expands from 8 liter to 12 liter with external pressure of 900 Pa, what is the work done on the system?

a) 3.6 Joule

b) – 3.6 Joule

c) 7.2 Joule

d) – 7.2 Joule

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11. You shake a thermos so that the temperature of tea inside increases by 2^{o}C, if you transferred Q amount of heat to the thermos, which of the following satisfies Q?

a) Q > 0

b) Q < 0

c) Q = 0

d) Cannot say

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12. Q amount of heat is transferred in an adiabatic process, which of the following is correct?

a) Q > 0

b) Q = 0

c) Q < 0

d) Cannot say

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13. Q amount of heat is transferred to a system, which of the following is correct?

a) Q > 0

b) Q < 0

c) Q = 0

d) Cannot say

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14. Temperature of a system is increased with no change in internal energy, if the work done by the system is 10 Joule, what amount of heat is taken out from the system?

a) 10 J

b) – 10 J

c) 0

d) 5 J

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15. Ratio heat transferred from 37^{o}C to a colder body and from that body to – 11^{o}C is 2, what is the temperature of colder body if surface areas are same for all bodies?

a) – 5^{o}C

b) – 3^{o}C

c) 5^{o}C

d) 9^{o}C

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^{o}C.

## Set 5

1. For an open unsteady state system, 5 J of heat was supplied and 10 J of work was done on the system, what is the value of change in enthalpy?

a) 5 J

b) 10 J

c) 15 J

d) 20 J

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2. For an open unsteady state system, 10 J of heat was supplied and 10 J of work was done by the system, what is the value of change in enthalpy?

a) 0

b) 10 J

c) 20 J

d) – 20 J

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3. For an open unsteady state system, 5 J of heat was supplied and 10 J of work was done by the system, what is the value of change in enthalpy?

a) – 5 J

b) 5 J

c) 10 J

d) 15 J

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4. For an open unsteady state system, 15 J of heat was taken off and 10 J of work was done by the system, what is the value of change in enthalpy?

a) – 5 J

b) 5 J

c) 25 J

d) – 25 J

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5. For an open unsteady state system, 15 J of heat was supplied and -5 J of work was done on the system, what is the value of change in enthalpy?

a) 10 J

b) – 15 J

c) 20 J

d) – 25 J

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6. Which of the following represents vaporization?

a) Change of vapor to liquid

b) Change of vapor to solid

c) Change of solid to vapor

d) Change of liquid to vapor

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7. Which of the following can definitely cause vaporization?

a) Heating a liquid

b) Heating a liquid at constant pressure

c) Cooling a liquid

d) Cooling a liquid at constant volume

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8. Vaporization starts at which point?

a) Dew point

b) Bubble point

c) Triple point

d) None of the mentioned

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9. What is the vaporization temperature of water at standard conditions?

a) 100^{o}F

b) 212^{o}F

c) 345^{o}F

d) 432^{o}F

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^{o}C = 212

^{o}F.

10. What is the point of saturation of a condensable vapor?

a) Bubble point

b) Boiling point

c) Triple point

d) Dew point