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MCQOPTIONS
This section includes 430 Mcqs, each offering curated multiple-choice questions to sharpen your Thermodynamics knowledge and support exam preparation. Choose a topic below to get started.
| 351. |
One bar pressure is the same as |
| A. | 1000 N/m2 |
| B. | 100 N/m2 |
| C. | 100,000 N/m2 |
| D. | 1 N/m2 |
| E. | 1000,000 N/m2 |
| Answer» D. 1 N/m2 | |
| 352. |
In which of the following energy conversion takes place at ambient temperature? |
| A. | Solar radiation |
| B. | Pulsejet |
| C. | Thermionic generator |
| D. | Magnetohydrodynamic conversion |
| E. | Battery producing electrical energy |
| Answer» F. | |
| 353. |
In a closed system, the change in enthalpy will be equal to the heat transferred when a reversible process takes place at constant |
| A. | Pressure |
| B. | Volume |
| C. | Entropy |
| D. | Temperature |
| E. | Internal energy |
| Answer» B. Volume | |
| 354. |
On a temperature-entropy diagram the slope of constant pressure line is given by |
| A. | S/T |
| B. | Cv/T |
| C. | T/Cp |
| D. | T/Cv |
| E. | T/S |
| Answer» D. T/Cv | |
| 355. |
The RMS velocity of hydrogen gas at N.T.P. is nearly |
| A. | 4839 m/s |
| B. | 839 m/s |
| C. | 1839 m/s |
| D. | 2839 m/s |
| E. | 3839 m/s |
| Answer» D. 2839 m/s | |
| 356. |
The mixing process of two fluids is always considered as |
| A. | reversible or irreversible depending upon the gases involved |
| B. | Pulsejet |
| C. | reversible |
| D. | irreversible |
| Answer» F. | |
| 357. |
A gas which obeys kinetic theory perfectly is known as |
| A. | Diatomic gas |
| B. | Monoatomic gas |
| C. | Perfect gas |
| D. | Pure gas |
| E. | Real gas |
| Answer» D. Pure gas | |
| 358. |
The critical pressure at which latent heat of vaporisation for water is zero is |
| A. | 250.6 kg/cm2 |
| B. | 100 kg/cm2 |
| C. | 228.6 kg/cm2 |
| D. | 235.6 kg/cm2 |
| E. | 215.1 kg/cm2 |
| Answer» D. 235.6 kg/cm2 | |
| 359. |
Planck's law of radiation is applicable to |
| A. | Radiation of any kind |
| B. | Temperature radiation |
| C. | Monochromatic radiation |
| D. | Thermal radiation |
| E. | None of the above |
| Answer» F. | |
| 360. |
The energy required to heat 1 gm of water from 0?F to 0?C will be nearly |
| A. | 32 cal |
| B. | 74.6 J |
| C. | Pulsejet |
| D. | zero |
| E. | 32 J |
| Answer» C. Pulsejet | |
| 361. |
Thermal efficiency of most of the internal combustion engines lies in the range |
| A. | 50 to 75 percent |
| B. | 90 to 100 percent |
| C. | 20 to 35 percent |
| D. | 75 to 90 percent |
| E. | 35 to 50 percent |
| Answer» D. 75 to 90 percent | |
| 362. |
The adiabatic horse power required to deliver 4 cu. M per minute of free air from 1 ata and 15?C to a received pressure at 7 ata would be in the range |
| A. | 20 ? 25 |
| B. | 5 ? 7 |
| C. | 7 ? 10 |
| D. | 15 ? 20 |
| E. | 10 ? 15 |
| Answer» B. 5 ? 7 | |
| 363. |
For a gas the difference between the values of Cp and Cv aceounts for |
| A. | external work done |
| B. | increased kinetic energy of molecules |
| C. | increase in volume is more rapid as compared to that of pressure |
| D. | None of the above |
| E. | Pulsejet |
| Answer» B. increased kinetic energy of molecules | |
| 364. |
In an automobile the gear box is fitted between |
| A. | Differential and wheels |
| B. | Engine and clutch |
| C. | Engine and flywheels |
| D. | Clutch and wheels |
| E. | Clutch and differential |
| Answer» F. | |
| 365. |
A body of weight 100 N falls freely through a distance of 10 m against an atmospheric drag force of 5 N. Considering the body as the system, the work interaction is |
| A. | 250 Nm |
| B. | 1050 Nm |
| C. | 1000 Nm |
| D. | Pulsejet |
| E. | 50 Nm |
| Answer» F. | |
| 366. |
The general gas equation is |
| A. | PVn = constant |
| B. | PV = (RT)m |
| C. | PV = constant |
| D. | PV = mRT |
| E. | PV = RT |
| Answer» E. PV = RT | |
| 367. |
Brayton cycles processes are |
| A. | Two isothermals constant volume a constant pressure |
| B. | One constant pressure, one constant volume, two adiabatics |
| C. | Two isentropics and two constant pressure |
| D. | Two isothermals and two isentropics |
| E. | Two isentropics and two constant volume |
| Answer» D. Two isothermals and two isentropics | |
| 368. |
Other factors remaining constant, if the temperature of sink is increased, the efficiency of the Carnot engine will |
| A. | increase or decrease depending upon temperature ratio |
| B. | will not change |
| C. | Pulsejet |
| D. | increase |
| E. | decrease |
| Answer» F. | |
| 369. |
Which of the following gas has the highest values for the adiabatic index? |
| A. | Air |
| B. | Helium |
| C. | Methane |
| D. | Oxygen |
| E. | Nitrogen |
| Answer» C. Methane | |
| 370. |
If a closed circuit is made of two dissimilar metals, an electric current flows in the circuit whdn the two junctions are maintained at different temperatures. This phenomenon is known as |
| A. | Seeback effect |
| B. | Peltier effect |
| C. | Maxwell's effect |
| D. | Faraday's effect |
| E. | Thomson effect |
| Answer» B. Peltier effect | |
| 371. |
If the sun becomes twice as hot |
| A. | its output of radiation energy will fall |
| B. | it will radiate predominantly in infra-red |
| C. | it will disintegrate into fragments |
| D. | Pulsejet |
| E. | it will radiate predominantly ultraviolet |
| Answer» F. | |
| 372. |
One kg of water is evaporated from 6 kg of sea water containing 4% salt. The percentage of salt in the remaining solution will be |
| A. | 4% |
| B. | 6% |
| C. | 3.33% |
| D. | 4.80% |
| E. | 1% |
| Answer» E. 1% | |
| 373. |
The efficiency of a Carnot engine is given as 0.75. If the cycle direction is reversed, what will be the value of COP of reversed Carnot cycle |
| A. | 0.33 |
| B. | 0.25 |
| C. | 1.33 |
| D. | 0.75 |
| E. | 4 |
| Answer» B. 0.25 | |
| 374. |
Heat is transferred from an insulated steam pipe to the surrounding still air by |
| A. | Conduction |
| B. | Radiation |
| C. | All the above together |
| D. | Forced convection |
| E. | Free convection |
| Answer» F. | |
| 375. |
Rankine cycle efficiency for a power plant is 29.6%. The Carnot cycle efficiency will be |
| A. | Equal to Rankine cycle efficiency |
| B. | More than Rankine cycle efficiency |
| C. | Less than Rankine cycle efficiency |
| D. | There is no comparison for the two |
| E. | None of the above |
| Answer» C. Less than Rankine cycle efficiency | |
| 376. |
Three Carnot engines A, B and C having source temperature of 750?K, 700?K and 650?K have sink temperatures respectively 400?k, 350?k and 300?k. Which engine is the least efficient? |
| A. | All being Carnot engine have identical efficiencies |
| B. | Pulsejet |
| C. | Engine B |
| D. | Engine C |
| E. | Engine A |
| Answer» F. | |
| 377. |
Other factors remaining constant, if the temperature of source is increased, the efficiency of Carnot engine will |
| A. | will not change |
| B. | decrease |
| C. | Pulsejet |
| D. | increase or decrease depending upon temperature ratio |
| E. | increase |
| Answer» F. | |
| 378. |
Which of the following cycle is less efficient than the remaining? |
| A. | Ericsson cycle |
| B. | Stirling cycle |
| C. | Otto cycle |
| D. | Pulsejet |
| E. | Carnot cycle |
| Answer» D. Pulsejet | |
| 379. |
The air standard efficiency of a turbine cycle is 57%. Which one of the following may be Carnot efficiency between the temperature limits of the cycle? |
| A. | 57% |
| B. | 50% |
| C. | 64% |
| D. | 55% |
| E. | 100% |
| Answer» D. 55% | |
| 380. |
A Rankine cycle working with saturated steam differs thermodynamically from a Carnot cycle only in the fact that |
| A. | The Carnot cycle cannot be used for vapour |
| B. | Steam is not the working substance for Carnot cycle |
| C. | There are more than two sources of heat in Rankine cycle |
| D. | Heat is supplied to the water at temperatures below the maximum temperature of the cycle |
| E. | None of the above |
| Answer» E. None of the above | |
| 381. |
A piece of paper wrapped tightly on a copper rod will get charred relatively slowly when held over a flame as compared to a piece of paper wrapped tightly on any of the following rod except |
| A. | silver rod |
| B. | iron rod |
| C. | Pulsejet |
| D. | brass rod |
| E. | wooden rod |
| Answer» B. iron rod | |
| 382. |
"What two dissimilar metals are heated at one end cooled at the other c.m.f. is developed proportional to difference of temperatures at two ends". Which of the following name is associated with the above statement? |
| A. | Euler |
| B. | Peltier-Thomson |
| C. | Gay-Lussac |
| D. | Faraday |
| E. | Kelvin-planck |
| Answer» C. Gay-Lussac | |
| 383. |
"Heat can flow from cold substance to hot substance with the aid of external work". Which of the following name is associated with the above statement? |
| A. | Gay Lussac |
| B. | Clausius |
| C. | Planck |
| D. | Kelvin |
| E. | Joule |
| Answer» C. Planck | |
| 384. |
"It is impossible to construct a heat engine which operates in a cycle and receives a given amount of heat from a high temperature body and does equal amount of work". Which of the following name is associated with the above statement? |
| A. | Gay Lussac |
| B. | Kinetic theory |
| C. | Kelvin-planck |
| D. | Joule-thomson |
| E. | None of the above |
| Answer» D. Joule-thomson | |
| 385. |
The charge in a Diesel engine consists of |
| A. | Air + diesel + lubricating oil |
| B. | Diesel + lubricating oil |
| C. | Air + lubricating oil |
| D. | Air |
| E. | Air + diesel |
| Answer» E. Air + diesel | |
| 386. |
The statement that the volume of a mixture of ideal gases is equal to the span of the partial volumes which the constituent gases would occupy if each existed alone at the pressure and temperature of the mixture, is known as |
| A. | Clapeyrons law |
| B. | Maxwell's law |
| C. | Leduc's law |
| D. | Daltons law |
| E. | Clausius law |
| Answer» D. Daltons law | |
| 387. |
Which of the following statement about Vanc der Waal's equation is valid? |
| A. | Pulsejet |
| B. | It represents a straight line on pv versus v plot |
| C. | The equation is valid for diatomic gases only |
| D. | It is valid for all pressures and temperatures |
| E. | It has three roots of identical value at the critical point |
| Answer» F. | |
| 388. |
Which is incorrect statement about the reversible process? |
| A. | A reversible process is ideal |
| B. | A reversible process must pass through a continuous series of equilibrium states |
| C. | A reversible process when undone, will leave no history of the events in the surroundings |
| D. | A reversible process must pass through the same states on the reversed path as were initially visited on the forward path |
| E. | None of the above |
| Answer» F. | |
| 389. |
In a diesel engine fuel is injected |
| A. | after the end of compression stroke |
| B. | at the beginning of compression stroke |
| C. | at the end of compression stroke |
| D. | before the end of compression stroke |
| E. | Pulsejet |
| Answer» E. Pulsejet | |
| 390. |
A petrol engine fuel that knocks at a low speed |
| A. | Pulsejet |
| B. | will have low fire point |
| C. | has a high octane rating |
| D. | will always knock at high speed |
| E. | may not knock at high speed |
| Answer» E. may not knock at high speed | |
| 391. |
Which of the following is the best fuel for diesel engines? |
| A. | Olefins |
| B. | Pulsejet |
| C. | Aromatics |
| D. | Naphthenes |
| E. | Paraffins |
| Answer» F. | |
| 392. |
Which of the following is a non-petroleum fuel? |
| A. | Diesel oil |
| B. | Petrol |
| C. | Naphtha |
| D. | Alcohol |
| E. | All of the above |
| Answer» E. All of the above | |
| 393. |
Diesel cycle processes are |
| A. | Two isentropic, one constant volume one constant pressure |
| B. | Isentropic, isothermal, constant volume, constant pressure |
| C. | Two constant volume, one constant pressure, one isothermal |
| D. | Two isentropic and two isothermal |
| E. | Two constant pressure, one constant volume, one isentropic |
| Answer» B. Isentropic, isothermal, constant volume, constant pressure | |
| 394. |
In case of a four cylinder diesel engine, the heat carried away by exhaust gases will be |
| A. | 10 to 20 percent |
| B. | 50 to 70 percent |
| C. | 25 to 35 percent |
| D. | 5 to 7 percent |
| E. | 7 to 10 percent |
| Answer» D. 5 to 7 percent | |
| 395. |
Which of the following is the best fuel for S.I. engines? |
| A. | Naphthenes |
| B. | Olefins |
| C. | Aromatics |
| D. | Pulsejet |
| E. | Paraffins |
| Answer» D. Pulsejet | |
| 396. |
The percentage of carbondioxide in the exhaust gases from a diesel engine cannot exceed |
| A. | 40% |
| B. | 50.50% |
| C. | 29% |
| D. | 36% |
| E. | 55% |
| Answer» D. 36% | |
| 397. |
Work done by an expanding gas under adiabatic condition results in |
| A. | Temperature decrease |
| B. | Temperature decreases first and then increase |
| C. | Temperature increase first and then decrease |
| D. | No change in temperature |
| E. | Temperature increase |
| Answer» B. Temperature decreases first and then increase | |
| 398. |
For a closed system, the difference between the heat added to the system and the work done by the system is equal to the change in |
| A. | entropy |
| B. | enthalpy |
| C. | internal energy |
| D. | Pulsejet |
| E. | temperature |
| Answer» D. Pulsejet | |
| 399. |
The area inside the PV diagram for a diesel engine represents |
| A. | heat supplied |
| B. | work done |
| C. | work supplied |
| D. | Pulsejet |
| E. | change in entropy |
| Answer» C. work supplied | |
| 400. |
The process in which the change in internal energy of a gas is equal to the work done is known as |
| A. | adiabatic process |
| B. | isochoric process |
| C. | isobaric process |
| D. | isothermal process |
| E. | Pulsejet |
| Answer» B. isochoric process | |