MCQOPTIONS
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MCQOPTIONS
This section includes 1092 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
The internal energy of a perfect gas is a function of |
| A. | pressure change &temperature |
| B. | temperature change &specific heat |
| C. | pressure & work supplied |
| D. | temperature |
| Answer» E. | |
| 102. |
Air is compressed isothermally by performing work equal to 16 KJ upon it. The change in internal energy is |
| A. | - 16 kj |
| B. | zeroth law of thermodynamics |
| C. | 16 kj |
| D. | 32 kj |
| Answer» C. 16 kj | |
| 103. |
If all the variables of a stream are independent of time it is said to be in |
| A. | steady flow |
| B. | unsteady flow |
| C. | uniform flow |
| D. | closed flow |
| Answer» B. unsteady flow | |
| 104. |
At any dbt, the the difference of wbt reading below below dbt, is the amount of water vapour held in mixture. |
| A. | smaller, smaller |
| B. | greater, greater |
| C. | greater, smaller |
| D. | smaller, greater |
| Answer» D. smaller, greater | |
| 105. |
The degree of saturation is the ratio of |
| A. | (saturated specific humidity / actual specific humidity)^2 |
| B. | 1/(saturated specific humidity * actual specific humidity) |
| C. | saturated specific humidity / actual specific humidity |
| D. | actual specific humidity / saturated specific humidity |
| Answer» E. | |
| 106. |
When humidity ratio of air air is said to be dehumidified. |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | none of the mentioned |
| Answer» C. remains constant | |
| 107. |
The total entropy of a mixture of gases is the of the partial entropies. |
| A. | average |
| B. | weighted mean |
| C. | sum |
| D. | difference of the highest and the lowest |
| Answer» D. difference of the highest and the lowest | |
| 108. |
An application requires R-12 at −140°C. The triple-point temperature is −157°C. Find the pressure of the saturated vapour at the required condition. |
| A. | 0.0058 kpa |
| B. | 0.0098 kpa |
| C. | 0.0068 kpa |
| D. | 0.0088 kpa |
| Answer» C. 0.0068 kpa | |
| 109. |
Water on melting and has the fusion curve with a slope. |
| A. | contracts, negative |
| B. | contracts, positive |
| C. | expands, negative |
| D. | expands, positive |
| Answer» B. contracts, positive | |
| 110. |
The slope of sublimation curve is the slope of the vaporization curve at triple point. |
| A. | equal to |
| B. | less than |
| C. | greater than |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 111. |
At the triple point, l(sublimation) = l(vaporization) – l(fusion). |
| A. | true |
| B. | false |
| Answer» C. | |
| 112. |
If a relation exists among variables x,y,z then z may be expressed as a function of x and y as, dz=Mdx+Ndy . |
| A. | true |
| B. | false |
| Answer» B. false | |
| 113. |
Which of the following is not a Maxwell equation? |
| A. | (∂t/∂v) = -(∂p/∂s) |
| B. | (∂t/∂p) = -(∂v/∂s) c) (∂p/∂t) = (∂s/∂v) d) (∂v/∂t) = -(∂s/∂p) |
| Answer» C. | |
| 114. |
A pure substance which exists in a single phase has independent variables. |
| A. | zero |
| B. | one |
| C. | two |
| D. | three |
| Answer» D. three | |
| 115. |
The temperature of feedwater leaving a heater is the saturation temperature at steam extraction pressure. |
| A. | less than |
| B. | equal to |
| C. | more than |
| D. | none of the mentioned |
| Answer» B. equal to | |
| 116. |
An 80 litre vessel contains 4 kg of R-134a at a pressure of 160 kPa. Determine the volume occupied by the vapour phase. |
| A. | 0.0775 m3 |
| B. | 0.0575 m3 |
| C. | 0.0975 m3 |
| D. | 0.0375 m3 |
| Answer» B. 0.0575 m3 | |
| 117. |
The properties of liquid with pressure. |
| A. | do not vary |
| B. | vary largely |
| C. | vary little |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 118. |
For proper utilization of exergy, it is desirable to make first law efficiency and the source and use temperatures should |
| A. | as close to unity, be different |
| B. | as close to unity, match |
| C. | as close to zero, match |
| D. | as close to zero, be different |
| Answer» C. as close to zero, match | |
| 119. |
If work is involved, Amin= and if heat is involved, Amin= |
| A. | w, q(1+to/t) |
| B. | w, q(1-to/t) |
| C. | q(1+to/t), w |
| D. | q(1-to/t), w |
| Answer» C. q(1+to/t), w | |
| 120. |
The rate at which entropy is transferred out must the rate at which entropy enters the control volume. |
| A. | be less than |
| B. | equal to |
| C. | exceed |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 121. |
The rate of entropy increase of the control volume or the net rate of entropy transfer to it. |
| A. | exceeds or is less than |
| B. | exceeds, is equal to |
| C. | is less than, or equal to |
| D. | none of the mentioned |
| Answer» C. is less than, or equal to | |
| 122. |
Whenever heat is transferred through a finite temperature difference, there is always a decrease in the availability of energy so transferred. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 123. |
The available energy is known as and the unavailable energy is known as |
| A. | energy, exergy |
| B. | exergy, energy |
| C. | both are called exergy |
| D. | both are called energy |
| Answer» C. both are called exergy | |
| 124. |
4 APPLICATIONS OF II LAW. HIGH AND LOW GRADE ENERGY. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 125. |
The obtainable from a certain heat input in a cyclic heat engine is called |
| A. | minimum work output, available energy |
| B. | maximum work output, available energy |
| C. | minimum work input, unavailable energy |
| D. | none of the mentioned |
| Answer» C. minimum work input, unavailable energy | |
| 126. |
The part of available for conversion is referred to |
| A. | high grade energy, available energy |
| B. | low grade energy, available energy |
| C. | low grade energy, unavailable energy |
| D. | high grade energy, unavailable energy |
| Answer» C. low grade energy, unavailable energy | |
| 127. |
The entropy of an isolated system can never |
| A. | increase |
| B. | decrease |
| C. | be zero |
| D. | none of the mentioned |
| Answer» C. be zero | |
| 128. |
For a reversible heat pump, COP is given by |
| A. | t2/(t1-t2) |
| B. | t1/(t1-t2) |
| C. | t2/(t2-t1) |
| D. | t1/(t2-t1) |
| Answer» C. t2/(t2-t1) | |
| 129. |
According to Carnot’s theorem, all heat engines operating between a given constant temperature source and sink, none has a higher efficiency than a reversible engine. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 130. |
2 STATEMENTS OF SECOND LAW AND ITS COROLLARIES. CARNOT CYCLE REVERSED CARNOT CYCLE, PERFORMANCE. CLAUSIUS INEQUALITY. |
| A. | high, low, receives |
| B. | low, high, receives |
| C. | high, low, gives |
| D. | low, high, gives |
| Answer» C. high, low, gives | |
| 131. |
A TER which transfers heat to system is called and one which receives heat is called |
| A. | source, sink |
| B. | sink, source |
| C. | sink, sink |
| D. | source, source |
| Answer» B. sink, source | |
| 132. |
Efficiency of a heat engine is defined as |
| A. | total heat output / net work input |
| B. | total heat input / net work output |
| C. | net work output / total heat input |
| D. | net work input / total heat output |
| Answer» D. net work input / total heat output | |
| 133. |
The Kelvin temperature is numerically equal to the and may be measured by means of a |
| A. | gas temperature, liquid thermometer |
| B. | ideal gas temperature, gas thermometer |
| C. | ideal gas temperature, liquid thermometer |
| D. | none of the mentioned |
| Answer» C. ideal gas temperature, liquid thermometer | |
| 134. |
The statement of third law is also called the Fowler-Guggenheim statement of the third law. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 135. |
Which law is stated here, “It is impossible to reduce any system to the absolute zero of temperature in a finite number of operations. |
| A. | first law of thermodynamics |
| B. | second law of thermodynamics |
| C. | third law of thermodynamics |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 136. |
A definite zero point on the absolute temperature scale but this point be reached violation of the second law. |
| A. | doesnot, can, without |
| B. | exists, cannot, without |
| C. | exists, can, with |
| D. | none of the mentioned |
| Answer» C. exists, can, with | |
| 137. |
When the heat transferred isothermally between the given decreases, the temperature |
| A. | isotherms, increases |
| B. | isotherms, decreases |
| C. | adiabatics, increases |
| D. | adiabatics, decreases |
| Answer» E. | |
| 138. |
The greater the temperature, the is the vapour pressure. |
| A. | lower |
| B. | higher |
| C. | depends on the substance |
| D. | none of the mentioned |
| Answer» C. depends on the substance | |
| 139. |
When two equilibrium states are infinitesimally near, |
| A. | dq/t=ds |
| B. | dq/t>ds |
| C. | dq/t<ds |
| D. | none of the mentioned |
| Answer» B. dq/t>ds | |
| 140. |
All engineering process, strictly speakingare |
| A. | reversible cycle |
| B. | irreversible |
| C. | quasti-static |
| D. | thermodynamically inequillibrium |
| Answer» E. | |
| 141. |
Change of entropy depends upon whichof the following? |
| A. | change of heat |
| B. | change of specific heats |
| C. | change of pressure &volume |
| D. | none of the above |
| Answer» B. change of specific heats | |
| 142. |
A chip dissipates 2 kJ of electric work and rejects it as heat transfer from its surface which is at 50°C to 25°C air. How much entropy is generated in the chip? |
| A. | 4.19 j/k |
| B. | 5.19 j/k |
| C. | 6.19 j/k |
| D. | 7.19 j/k |
| Answer» D. 7.19 j/k | |
| 143. |
In the polytropic process equation pvⁿ = constant, if n is infinitely large, theprocess is termed as |
| A. | constant volume |
| B. | constant pressure |
| C. | constant temperature |
| D. | adiabatic |
| Answer» B. constant pressure | |
| 144. |
Phase change occurs at |
| A. | constant pressure |
| B. | constant temperature |
| C. | constant pressure and temperature |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 145. |
For ……. The internal energy & enthalpy are the functions of temperature only |
| A. | perfect gas |
| B. | water in pipes surrounded by steam |
| C. | saturated steam |
| D. | superheated steam |
| Answer» B. water in pipes surrounded by steam | |
| 146. |
Rankine cycle operating on low pressure limit of p1 & high pressure limit p2 |
| A. | has higher thermal efficiency than the carnot cycle operating between same pressure limits |
| B. | has lower thermal efficiency than carnot cycle operating between same pressurelimits |
| C. | has same thermal efficiency than carnot cycle operating between same pressure limits |
| D. | may be more or less depending upon the magnitudes of p1 & p2 |
| Answer» B. has lower thermal efficiency than carnot cycle operating between same pressurelimits | |
| 147. |
Correlate the following statements i) by reducing the condenser pressure in a Rankine cycle work output is increasedii) increased proportion of moisture in turbine is undesirable because water particles erode the blades |
| A. | both i) & ii) are independently true |
| B. | both i) & ii) are not true |
| C. | i) is true but ii) is not |
| D. | ii) is true but i) is not |
| Answer» B. both i) & ii) are not true | |
| 148. |
The first TdS equation is |
| A. | tds=cv*dt + t(∂t/∂p)dv |
| B. | tds=cv*dt – t(∂p/∂t)dv |
| C. | tds=cv*dt + t(∂p/∂t)dv |
| D. | tds=cv*dt – t(∂t/∂p)dv |
| Answer» D. tds=cv*dt – t(∂t/∂p)dv | |
| 149. |
On which of the following laws measurement of temperature is based? |
| A. | joule\s law |
| B. | zeroth law of thermodynamics |
| C. | first law of thermodynamics |
| D. | second law of thermodynamics |
| Answer» C. first law of thermodynamics | |
| 150. |
The specific heat of a gas is a function of |
| A. | temperature only |
| B. | temperature & pressure |
| C. | temperature & entropy |
| D. | temperature, pressure& entropy |
| Answer» B. temperature & pressure | |