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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.
| 151. |
A Rankine cycle has efficiency of 19.4%. The steam enters the turbine with enthalpy of 32.85 kJ/Kg while heat of water entering the boiler is 423.6 kJ/Kg.the work of the turbine is 560 kJ/ Kg. the pump work is |
| A. | 3.5 kj/kg |
| B. | 5 kj/kg |
| C. | 6.5 kj/kg |
| D. | 7 kj/kg |
| Answer» C. 6.5 kj/kg | |
| 152. |
SI unit of enthalpy is |
| A. | joule/kgk |
| B. | joule/k |
| C. | joule/kg |
| D. | k/kg |
| Answer» D. k/kg | |
| 153. |
The extension & compression of a helicalspring is an example of |
| A. | irreversible process |
| B. | reversible process |
| C. | isothermal process |
| D. | adiabatic process |
| Answer» C. isothermal process | |
| 154. |
The friction present in moving devices makes a process reversible. |
| A. | true |
| B. | false |
| Answer» C. | |
| 155. |
Entropy in statistical thermodynamics isdefined as |
| A. | a universal property |
| B. | reversible heat transfer |
| C. | degree of randomness |
| D. | d)measure of reversibilityof a system |
| Answer» D. d)measure of reversibilityof a system | |
| 156. |
In a Carnot cycle which of the followingprocessez must be carried out at extremely slow speed? |
| A. | isothermal compression |
| B. | adiabatic expansion |
| C. | adiabatic compression |
| D. | none of the above |
| Answer» B. adiabatic expansion | |
| 157. |
Entropy at absolute zero temperature iszero for a |
| A. | perfect gas |
| B. | perfect substance |
| C. | perfect crystal |
| D. | glass |
| Answer» D. glass | |
| 158. |
Both first law efficiency and second law efficiency indicate how effectively the input has been converted into the product. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 159. |
In a steam power plant which cycle requires two or more feed pumps |
| A. | regenerative rankine cycle |
| B. | reheat rankine cycle |
| C. | simple rankine cycle |
| D. | idealized regenerative rankine cycle |
| Answer» B. reheat rankine cycle | |
| 160. |
The first law of thermodynamics doesn’t tell us whether a thermodynamic process is feasible or not. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 161. |
In case of a heat pump, second law efficiency is given as |
| A. | (first law efficiency)*(1-ta/to) |
| B. | (first law efficiency)*(1+to/ta) |
| C. | (first law efficiency)*(1-to/ta) |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 162. |
In case of real gases, cp will be equal tocv |
| A. | at absolute zero |
| B. | at triple point |
| C. | at critical temperature |
| D. | above criticaltempeature |
| Answer» B. at triple point | |
| 163. |
Which statement is wrong for adiabaticexpansion |
| A. | h = 0 |
| B. | w = 0 |
| C. | ds = 0 |
| D. | w+e = 0 |
| Answer» E. | |
| 164. |
……….. Is the unit of entropy |
| A. | j/kg |
| B. | j/kg k |
| C. | j/k |
| D. | j/kgs |
| Answer» C. j/k | |
| 165. |
On which of the following factors does air standard efficiency of a diesel cycledepend? |
| A. | adiabatic compression ratio |
| B. | ratio of specific heats |
| C. | cut-off ratio |
| D. | all of the above |
| Answer» E. | |
| 166. |
An inventor claims that a new heat cycle will develop 0.4 kW for a heat addition of32.5 kJ/mm. The temperature of heat source is 1990 K & that of sink is 850K. Is his claim true? |
| A. | true |
| B. | false |
| C. | either of the above |
| D. | unpredictable |
| Answer» C. either of the above | |
| 167. |
For a reversible refrigerator, Coefficient of Performance is given by |
| A. | t2/(t1-t2) |
| B. | t1/(t1-t2) |
| C. | t2/(t2-t1) |
| D. | t1/(t2-t1) |
| Answer» B. t1/(t1-t2) | |
| 168. |
The latent enthalpy of vapourisation at criticalpoint is |
| A. | zero |
| B. | minimum |
| C. | maximum |
| D. | none of the above |
| Answer» B. minimum | |
| 169. |
Temperature of a gas is produced due towhich of the following? |
| A. | attraction of molecules |
| B. | repulsion of molecules |
| C. | kinetic energy of molecules |
| D. | all of the above |
| Answer» D. all of the above | |
| 170. |
Cooling towers are rated in terms of |
| A. | approach |
| B. | range |
| C. | both of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 171. |
In adiabatic evaporative cooling, heat transfer between chamber and surroundings is |
| A. | zero |
| B. | high |
| C. | low |
| D. | none of the mentioned |
| Answer» B. high | |
| 172. |
For the ideal gas equation, what assumptions are made? |
| A. | there is little or no attraction between the molecules of the gas |
| B. | the volume occupied by the molecules is negligibly small compared to the volume of the gas |
| C. | both of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 173. |
The equation for the average kinetic energy is |
| A. | 0.5 kt |
| B. | 1.5 kt |
| C. | 2.5 kt |
| D. | 3.5 kt |
| Answer» C. 2.5 kt | |
| 174. |
5 P-V DIAGRAM. |
| A. | saturated solid line |
| B. | saturated liquid lines |
| C. | saturated vapour line |
| D. | all of the mentioned |
| Answer» E. | |
| 175. |
Which of the following is true for a closed heater? |
| A. | it requires a single pump regardless of the number of heaters |
| B. | it is costly |
| C. | both of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 176. |
A mixture of gases expands from 0.03 m³ to 0.06 m³ at a constant pressure of 1 Mpa & absorbs 84 kJ of heat during the process. The change in internal energy ofthe mixture is |
| A. | 30 kj |
| B. | 54 kj |
| C. | 84 kj |
| D. | 114 kj |
| Answer» C. 84 kj | |
| 177. |
The value of one bar (in SI units) is equalto |
| A. | 100 n/m?? |
| B. | 1000 n/m?? |
| C. | 1??10⁴ n/m?? |
| D. | 1??10⁵ n/m?? |
| Answer» E. | |
| 178. |
Maxwell’s equations consists of equations. |
| A. | four |
| B. | three |
| C. | two |
| D. | one |
| Answer» B. three | |
| 179. |
The gas constant of the mixture is the of the gas constants of the components. |
| A. | average |
| B. | weighted mean |
| C. | sum |
| D. | difference of the highest and the lowest |
| Answer» C. sum | |
| 180. |
The basis for measuring thermodynamic property of temperature is given by ……. Law of thermodynamics |
| A. | zeroth |
| B. | first |
| C. | second |
| D. | third |
| Answer» B. first | |
| 181. |
……….. Is an intensive property |
| A. | specific volume |
| B. | total volume |
| C. | total mass |
| D. | total energy of a system |
| Answer» B. total volume | |
| 182. |
A series of operations, which take place in a certain order & restore the initialcondition is known as |
| A. | reversible cycle |
| B. | irreversible cycle |
| C. | thermodynamic cycle |
| D. | none of the above |
| Answer» D. none of the above | |
| 183. |
The main cause of the irreversibility is |
| A. | mechanical & fluid friction |
| B. | unrestricted expansion |
| C. | heat transfer with a finite temperature difference |
| D. | all of the above |
| Answer» E. | |
| 184. |
Under which of the following conditionsall gases behave ideally? |
| A. | high pressure conditions |
| B. | law pressure conditions |
| C. | vaccum conditions |
| D. | all of the aboveconditions |
| Answer» C. vaccum conditions | |
| 185. |
In a regenerative Rankine cycle as compared to simple Rankine cycle |
| A. | the pump work is smaller |
| B. | the addition of heat is smaller |
| C. | the superheat is to lesser extent |
| D. | the heat rejected in condenser is smaller |
| Answer» E. | |
| 186. |
At critical pressure, value of Hg-Hf is |
| A. | two |
| B. | one |
| C. | zero |
| D. | infinity |
| Answer» D. infinity | |
| 187. |
In polytropic process pv?=C the value ofexponent n=±? is indicative of |
| A. | isobaric process |
| B. | isentropic process |
| C. | isochoric process |
| D. | throttling process |
| Answer» D. throttling process | |
| 188. |
Which of the following is not a propertyof the system |
| A. | temperature |
| B. | pressure |
| C. | specific volume |
| D. | heat |
| Answer» E. | |
| 189. |
Variations of pressure & volume atconstant temperature are correlated through |
| A. | charle\s law |
| B. | boyle\s law |
| C. | gas law |
| D. | gay lussac\s law |
| Answer» C. gas law | |
| 190. |
………. Is one in which neither any heatenters nor leaves the system |
| A. | isochoric process |
| B. | isobaric process |
| C. | isentropic process |
| D. | isothermal process |
| Answer» D. isothermal process | |
| 191. |
Which of the following statements regarding a perpetual motion machine is correct? |
| A. | it is an in efficient machine |
| B. | it is non-thermodynamic machine |
| C. | it is thermodynamic machine |
| D. | it is hypothetic machine whose operation would violate the laws of thermodynamics |
| Answer» E. | |
| 192. |
Which of the following is an intensive property of a thermodynamic system |
| A. | volume |
| B. | temperature |
| C. | mass |
| D. | energy |
| Answer» C. mass | |
| 193. |
The universal gas constant will be equal to difference between specific heats at constant pressure & constant volume for |
| A. | 1 kg mass of gas |
| B. | 1 molecule of gas |
| C. | 1 kg molecule of gas |
| D. | any mass of gas |
| Answer» D. any mass of gas | |
| 194. |
Boyle's law states that, when tempearture is constant, the volume of agiven mass of a perfect gas |
| A. | varies directly as the absolute pressure |
| B. | varies inversely as the absolute pressure |
| C. | varies as square of the absolute pressue |
| D. | does not vary with the absolute pressure |
| Answer» C. varies as square of the absolute pressue | |
| 195. |
Which of the following processes exhibit external mechanical irreversibility? |
| A. | isothermal dissipation of work |
| B. | adiabatic dissipation of work |
| C. | both of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 196. |
The reversible engines are |
| A. | least efficient |
| B. | most efficient |
| C. | having same efficiency asirreversible engines |
| D. | none of the above |
| Answer» C. having same efficiency asirreversible engines | |
| 197. |
During a constant pressure expansion of a gas 33.3 % heat is converted into work while the temperature rises by 20K. The specific heat of gas at constant pressureis |
| A. | 10% w |
| B. | 12 % w |
| C. | 15% w |
| D. | 20% w |
| Answer» D. 20% w | |
| 198. |
Kelvin-Plank's law deals with |
| A. | conservation of energy |
| B. | conservation of heat |
| C. | conservation of mass |
| D. | conversion of heat intowork |
| Answer» E. | |
| 199. |
Work done in a quasi-static process |
| A. | depends on the path followed |
| B. | independent of the path followed |
| C. | depends only on the initial and final states |
| D. | none of the mentioned |
| Answer» B. independent of the path followed | |
| 200. |
A rigid tank contains 10 kg of water at 90°C. If 8 kg of the water is in the liquid form and the rest is in the vapour form, determine the volume of the tank. |
| A. | 1.73 m3 |
| B. | 2.73 m3 |
| C. | 3.73 m3 |
| D. | 4.73 m3 |
| Answer» E. | |