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.
| 301. |
Essential parts of a power plant operating on aRankine cycle are |
| A. | engine or turbine |
| B. | engine or turbine & conderser |
| C. | engine or turbine, condenser, pump &boiler |
| D. | engine or turbine & boiler |
| Answer» D. engine or turbine & boiler | |
| 302. |
………. Is not a property of the system |
| A. | pressure |
| B. | temperature |
| C. | heat |
| D. | specific volume |
| Answer» D. specific volume | |
| 303. |
The main purpose of reheat Rankine cycle is |
| A. | to reduce moisture in steam & thus to protect turbine blading |
| B. | to obtain significant gain in efficiency |
| C. | to obtain significant gain in net work |
| D. | to reduce heat supplied & yet maintain turbine work |
| Answer» E. | |
| 304. |
Entropy is called the property of a system because |
| A. | it has same value at any two equilibrium states |
| B. | it depends upon the process path |
| C. | it has a unique value at each equilibrium state |
| D. | it does not change between two equilibriumstates |
| Answer» B. it depends upon the process path | |
| 305. |
Increase in entropy of a systemrepresents |
| A. | increase in availability ofenergy |
| B. | increase in temperature |
| C. | decrease in pressure |
| D. | degradation of energy |
| Answer» E. | |
| 306. |
The change of entropy when heat isabsorbed by the gas is |
| A. | positive |
| B. | negative |
| C. | positive or negative |
| D. | all of the above |
| Answer» B. negative | |
| 307. |
The cooling tower uses the phenomenon of evaporative cooling to cool warm water above the dbt of air. |
| A. | true |
| B. | false |
| Answer» C. | |
| 308. |
A Carnot cycle operates between source & sink temperatures of 250°C & - 15°C. If the system receives 90kJ from the source then the net worktransfer equals |
| A. | 30.5 kj |
| B. | 35.65 kj |
| C. | 45.54 kj |
| D. | 65.54 kj |
| Answer» D. 65.54 kj | |
| 309. |
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 | |
| 310. |
Which of the following is the extensive property of a thermodynamic system |
| A. | pressure |
| B. | volume |
| C. | temperature |
| D. | density |
| Answer» C. temperature | |
| 311. |
The area under the T-s (temperature - entropy) curve of any thermodynamicprocess represents |
| A. | heat rejected only |
| B. | heat absorbed only |
| C. | work done during the process |
| D. | heat absorbed or rejected |
| Answer» E. | |
| 312. |
For getting TdS equations, we assume entropy to be a function of T and V and also of T and p. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 313. |
What reaction takes place during photosynthesis? |
| A. | exothermic reaction |
| B. | endothermic reaction |
| C. | redox reaction |
| D. | combustion reaction |
| Answer» C. redox reaction | |
| 314. |
The process or systems that do not involve heat are called |
| A. | isothermal processes |
| B. | equilibrium processes |
| C. | adiabatic processes |
| D. | steady processes |
| Answer» D. steady processes | |
| 315. |
………. Law states that equal volume of all gases, at the same temperature & pressure, contains equal number ofmolecules |
| A. | boyle\s |
| B. | gay-lussac |
| C. | avogadro |
| D. | charle\s |
| Answer» D. charle\s | |
| 316. |
The first law of thermodynamics defines |
| A. | entropy |
| B. | internal energy |
| C. | work |
| D. | heat |
| Answer» C. work | |
| 317. |
If a substance goes though a cycle of changes returning back to original state,the change in entropy is |
| A. | positive |
| B. | negative |
| C. | zero |
| D. | positive or negative depending upon originalstate |
| Answer» C. zero | |
| 318. |
In which of the following processes theexternal work done is not zero? |
| A. | throttling |
| B. | free expansion |
| C. | constant volume process |
| D. | constant pressureprocess |
| Answer» E. | |
| 319. |
Air with initial condition of p1, v1 expands to final condition of p1/2, 3v1.The process is |
| A. | hyperbolic |
| B. | adiabatic |
| C. | polytropic with n > 1 |
| D. | polytropic with n < 1 |
| Answer» B. adiabatic | |
| 320. |
Which of the following exists in a p-V diagram for water? |
| A. | saturated solid line |
| B. | saturated liquid lines |
| C. | saturated vapour line |
| D. | all of the mentioned |
| Answer» E. | |
| 321. |
Mathematically a puresubstance can be written as |
| A. | p=f(t,v) |
| B. | v= f(p,t) |
| C. | t=f(p,v) |
| D. | any of the above |
| Answer» E. | |
| 322. |
If the path A causes more entropy generation than path B, then |
| A. | path a is more irreversible than path b |
| B. | path a involves more lost work |
| C. | both of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 323. |
Entropy occurs due to |
| A. | change in macroscopic variables |
| B. | volumetric changes only |
| C. | mass changes only |
| D. | temperature only |
| Answer» B. volumetric changes only | |
| 324. |
During a fluid flow, the temperature is developed due to |
| A. | increase in density |
| B. | change in pressure |
| C. | translational kinetic energy |
| D. | fluid level |
| Answer» D. fluid level | |
| 325. |
An engine receives 15152 J/s of heat & produces 5 KW of power. The efficiencyof the engine is |
| A. | 25% |
| B. | 27.5% |
| C. | 30% |
| D. | 33% |
| Answer» B. 27.5% | |
| 326. |
Which of the following processes arereversible processes? |
| A. | isothermal & adiabatic |
| B. | constant volume &constant pressure |
| C. | hyperbolic & pv?= constant |
| D. | none of the above |
| Answer» B. constant volume &constant pressure | |
| 327. |
Which of the following is an openthermodynamic system? |
| A. | pressure cooker |
| B. | manual ice cream freezer |
| C. | centrifugal pump |
| D. | none of the above |
| Answer» D. none of the above | |
| 328. |
The wet bulb temperature is the temperature recorded by moistened bulb. |
| A. | lowest |
| B. | highest |
| C. | atmospheric |
| D. | none of the mentioned |
| Answer» B. highest | |
| 329. |
In a Carnot engine, when the working substance rejects its heat to sink, the temperature of sink |
| A. | remains same |
| B. | decrease |
| C. | increases |
| D. | becomes 0??k |
| Answer» B. decrease | |
| 330. |
9) at 1 atm and 27oC? |
| A. | 23.4 liter |
| B. | 37.5 liter |
| C. | 42.1 liter |
| D. | 59.6 liter view answer |
| Answer» B. 37.5 liter | |
| 331. |
In a simple Rankine cycle steam was expanded from 100 bar & 380°C to 1 bar0.8 dry state. The pump motor consumes 10 kJ/kg of energy. The efficiency of cycle is |
| A. | 31% |
| B. | 34% |
| C. | 29.8% |
| D. | 30.6% |
| Answer» E. | |
| 332. |
What is the most preferable dryness |
| A. | 0.99 |
| B. | 0.77 |
| C. | 0.66 |
| D. | 0.88 |
| Answer» E. | |
| 333. |
The triple point is a line on the p-V diagram, where all the three phases, solid, liquid and gas exist. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 334. |
When two bodies are in thermal equilibrium with a third body they are also in thermal equilibrium with eachother. This statement is called |
| A. | zeroth law of thermodynamics |
| B. | first law of thermodynamics |
| C. | second law of thermodynamics |
| D. | kelvin planck\s law |
| Answer» B. first law of thermodynamics | |
| 335. |
A reversible engine performing as engine has efficiency of 62.5%. If it is reversed to work as refrigerator its COP will be |
| A. | 60% |
| B. | 62.5% |
| C. | 65% |
| D. | 37.5% |
| Answer» D. 37.5% | |
| 336. |
For an ideal gas, Z has the value |
| A. | 0 |
| B. | 2 |
| C. | 1 |
| D. | infinity |
| Answer» D. infinity | |
| 337. |
In a reversible cycle, the entropy of thesystem |
| A. | increases |
| B. | decreases |
| C. | does not change |
| D. | first increases & thendecreases |
| Answer» D. first increases & thendecreases | |
| 338. |
A process will be reversible if it has |
| A. | no dissipative effects |
| B. | dissipative effects |
| C. | depends on the given conditions |
| D. | none of the mentioned |
| Answer» B. dissipative effects | |
| 339. |
Regarding enthalpy which of the following statements is incorrect? |
| A. | it is the function of specific heat at constantvolume |
| B. | it is the extensive property of the system |
| C. | it is the sum of internal energy & the pressurevolume product |
| D. | it is the same as heat transfer during constantpressure process |
| Answer» B. it is the extensive property of the system | |
| 340. |
Internal energy & enthalpy of an ideal gasare functions of |
| A. | pressure only |
| B. | temperature only |
| C. | specific volume only |
| D. | temperature & pressure |
| Answer» C. specific volume only | |
| 341. |
Which of the following is an example of low grade energy? |
| A. | heat or thermal energy |
| B. | heat from nuclear fission or fusion |
| C. | heat from combustion of fossil fuel |
| D. | all of the mentioned |
| Answer» E. | |
| 342. |
Which of the following is used as a working substance for a Carnotcycle? |
| A. | ideal gas |
| B. | real gas |
| C. | steam |
| D. | atmospheric air |
| Answer» B. real gas | |
| 343. |
A power cycle using steam as working fluid consist ofi) constant pressure heat addition ii)adiabatic expansioniii) constant pressure heat rejection & iv) adiabatic compression. The cycle is |
| A. | simple rankine cycle |
| B. | modified rankine cycle |
| C. | carnot cycle |
| D. | regenerative rankine cycle |
| Answer» D. regenerative rankine cycle | |
| 344. |
A perpetual motion machine of first kind |
| A. | is a fictitious machine |
| B. | can supply mechanical work without dissipating energy |
| C. | violates first law |
| D. | all of the mentioned |
| Answer» E. | |
| 345. |
Which of the following is an example of high grade energy? |
| A. | mechanical work |
| B. | electrical energy |
| C. | water power and wind power |
| D. | all of the mentioned |
| Answer» E. | |
| 346. |
Adiabatic & isothermal processes areidentical at |
| A. | absolute zerotemperature |
| B. | below 0??c temperature |
| C. | saturation temperature |
| D. | critical temperature |
| Answer» B. below 0??c temperature | |
| 347. |
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 outside the chip? |
| A. | 0.419 j/k |
| B. | 0.519 j/k |
| C. | 0.619 j/k |
| D. | 0.719 j/k |
| Answer» C. 0.619 j/k | |
| 348. |
Efficiency of a reversible heat engine is given by |
| A. | 1-(t1/t2) |
| B. | 1-(t2/t1) |
| C. | (t1/t2)-1 |
| D. | (t2/t1)-1 |
| Answer» C. (t1/t2)-1 | |
| 349. |
Leaking of air from a punctured tube is anexample of |
| A. | isothermal expansion |
| B. | adiabatic expansion |
| C. | throttling |
| D. | constant pressureexpansion |
| Answer» D. constant pressureexpansion | |
| 350. |
Examine follwing two statements & choosethe correct relationshipi) for a steam power plant Rankine cycle is preferred over Carnot cycleii) a pump which will handle the mixture of vapour & liquid is difficult to construct |
| A. | both i) ii) are correct & i) is the consequence of ii) |
| B. | both i) & ii) are independently correct |
| C. | i) is correct but ii) is not |
| D. | ii) is correct but i) is not |
| Answer» B. both i) & ii) are independently correct | |