Engineering Thermodynamics MCQ Questions & Answers

61

Kelvin-Planck’s law deals with

A) Conservation of work B) Conservation of heat C) Conversion of work into heat D) Conversion of heat into work

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Answer & Solution

Answer: Option D

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62

The thermal efficiency of an ideal gas turbine plant is given by (where r = Pressure ratio)

A) $${{\text{r}}^{\gamma - 1}}$$ B) $$1 - {{\text{r}}^{\gamma - 1}}$$ C) $$1 - {\left( {\frac{1}{{\text{r}}}} \right)^{\frac{\gamma }{{\gamma - 1}}}}$$ D) $$1 - {\left( {\frac{1}{{\text{r}}}} \right)^{\frac{{\gamma - 1}}{\gamma }}}$$

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Answer & Solution

Answer: Option D

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63

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

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Answer & Solution

Answer: Option B

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64

Characteristic gas constant of a gas is equal to

A) $$\frac{{{{\text{C}}_{\text{p}}}}}{{{{\text{C}}_{\text{v}}}}}$$ B) $$\frac{{{{\text{C}}_{\text{v}}}}}{{{{\text{C}}_{\text{p}}}}}$$ C) $${{\text{C}}_{\text{p}}} - {{\text{C}}_{\text{v}}}$$ D) $${{\text{C}}_{\text{p}}} + {{\text{C}}_{\text{v}}}$$

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Answer & Solution

Answer: Option C

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65

The variables which control the physical properties of a perfect gas are

A) Pressure exerted by the gas B) Volume occupied by the gas C) Temperature of the gas D) All of these

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Answer & Solution

Answer: Option D

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66

According to Avogadro's Hypothesis

A) The molecular weights of all the perfect gases occupy the same volume under same conditions of pressure and temperature B) The sum of partial pressure of mixture of two gases is sum of the two C) Product of the gas constant and the molecular weight of an ideal gas is constant D) Gases have two values of specific heat

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Answer & Solution

Answer: Option A

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67

The following cycle is used for air craft refrigeration

A) Brayton cycle B) Joule cycle C) Carnot cycle D) Reversed Brayton cycle

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Answer & Solution

Answer: Option D

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68

In closed cycle gas turbine, the air is compressed

A) Isothermally B) Isentropically C) Polytropically D) None of these

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Answer & Solution

Answer: Option B

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69

A perfect gas at 27°C is heated at constant pressure till its volume is double. The final temperature is

A) 54°C B) 327°C C) 108°C D) 654°C

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Answer & Solution

Answer: Option B

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70

The amount of heat required to raise the temperature of __________ water through one degree is called kilojoules.

A) 1 g B) 10 g C) 100 g D) 1000 g

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Answer & Solution

Answer: Option D

Solution:

The amount of heat required to raise the temperature of 1000 g (or 1 kg) of water through one degree Celsius is called a kilojoule.
This is because the specific heat capacity of water is approximately 4.186 kJ/kg°C, meaning that 1 kg of water requires about 4.186 kJ to increase its temperature by 1°C.
The smaller masses such as 1 g, 10 g, or 100 g would require proportionally less heat energy.

Engineering Thermodynamics MCQ Questions & Answers | Mechanical Engineering