MCQOPTIONS
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MCQOPTIONS
This section includes 475 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.
| 451. |
The efficiency of Carnot cycle is maximum for_____________________? |
| A. | gas engine |
| B. | well lubricated engine |
| C. | petrol engine |
| D. | steam engine |
| E. | reversible engine |
| Answer» F. | |
| 452. |
If a system after undergoing a series of processes, returns to the initial state then__________________? |
| A. | process is thermodynamically in equilibrium |
| B. | process is executed in closed system cycle |
| C. | its entropy will change due to irreversibility |
| D. | sum of heat and work transfer will be zero |
| E. | no work will be done by the system |
| Answer» E. no work will be done by the system | |
| 453. |
The energy of molecular motion appears as________________? |
| A. | heat |
| B. | potential energy |
| C. | surface tension |
| D. | friction |
| E. | increase in pressure |
| Answer» B. potential energy | |
| 454. |
Water contained in a beaker can be made to boil by passing steam through it__________________? |
| A. | at atmospheric pressure |
| B. | at a pressure below the firuosphejric pressure |
| C. | at a pressure greater than atmospheric pressure |
| D. | any pressure |
| E. | not possible |
| Answer» D. any pressure | |
| 455. |
The door of a running refrigerator inside a room was left open____________________?
|
| A. | The room will be cooled to the temperature inside the refrigerator |
| B. | The room will be cooled very slightly |
| C. | The room will be gradually warmed up |
| D. | The temperature of the air in room will remain unaffected |
| E. | any one of above is possible depending on the capacity |
| Answer» D. The temperature of the air in room will remain unaffected | |
| 456. |
Which law states that the specific heat of a gas remains constant at all temperatures and pressures______________________? |
| A. | Charles’ Law |
| B. | Joule’s Law |
| C. | Regnault’s Law |
| D. | Boyle’s Law |
| E. | there is no such law |
| Answer» D. Boyle’s Law | |
| 457. |
First law of thermodynamics___________________? |
| A. | enables to determine change in internal energy of the system |
| B. | does not help to predict whether the system will or not undergo a change |
| C. | does not enable to determine change in entropy |
| D. | provides relationship between heat, work and internal energy |
| E. | all of the above |
| Answer» F. | |
| 458. |
Carnot cycle has maximum efficiency for__________________? |
| A. | reversible engine |
| B. | irreversible engine |
| C. | new engine |
| D. | petrol engine |
| E. | diesel engine |
| Answer» B. irreversible engine | |
| 459. |
According to first law of thermodynamics_______________________? |
| A. | mass and energy are mutually convertible |
| B. | Carnot engine is most efficient |
| C. | heat and work are mutually convertible |
| D. | mass and light are mutually convertible |
| E. | heat flows from hot substance to cold substance |
| Answer» D. mass and light are mutually convertible | |
| 460. |
In an isothermal process, the internal energy________________? |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | first increases and then decreases |
| E. | first decreases and then increases |
| Answer» D. first increases and then decreases | |
| 461. |
First law of thermodynamics furnishes the relationship between______________________? |
| A. | heat and work |
| B. | heat, work and properties of the system |
| C. | various properties of the system |
| D. | various thermodynamic processes |
| E. | heat and internal energy |
| Answer» C. various properties of the system | |
| 462. |
The unit of length in S.I. units is________________? |
| A. | meter |
| B. | centimeter |
| C. | kilometer |
| D. | millimeter |
| Answer» B. centimeter | |
| 463. |
An open system is one in which____________________? |
| A. | mass does not cross boundaries of the system, though energy may do so |
| B. | neither mass nor energy crosses the boundaries of the system |
| C. | both energy and mass cross the boundaries of the system |
| D. | mass crosses the boundary but not the energy |
| E. | thermodynamic reactions do not occur |
| Answer» D. mass crosses the boundary but not the energy | |
| 464. |
No liquid can exist as liquid at____________________? |
| A. | – 273 °K |
| B. | vacuum |
| C. | zero pressure |
| D. | centre of earth |
| E. | in space |
| Answer» D. centre of earth | |
| 465. |
Which of the following variables controls the physical properties of a perfect gas_________________? |
| A. | pressure |
| B. | temperature |
| C. | volume |
| D. | all of the above |
| E. | atomic mass |
| Answer» E. atomic mass | |
| 466. |
The unit of time in S.I. units is__________________? |
| A. | second |
| B. | minute |
| C. | hour |
| D. | day |
| E. | year |
| Answer» B. minute | |
| 467. |
The unit of temperature in S.I. units is _________________? |
| A. | Centigrade |
| B. | Celsius |
| C. | Fahrenheit |
| D. | Kelvin |
| E. | Rankine |
| Answer» E. Rankine | |
| 468. |
Universal gas constant is defined as equal to product of the molecular weight of the gas and_______________? |
| A. | specific heat at constant pressure |
| B. | specific heat at constant volume |
| C. | ratio of two specific heats |
| D. | gas constant |
| E. | unity |
| Answer» E. unity | |
| 469. |
Which analysis/analyses is/are required to make energy conversion or energy conveying system more efficient? |
| A. | First law or energy analysis |
| B. | Second law or exergy analysis |
| C. | Both a. and b. |
| D. | None of the above |
| Answer» D. None of the above | |
| 470. |
At ideal condition of vapour power cycle, reversible constant pressure heat rejection is carried out at |
| A. | boiler |
| B. | turbine |
| C. | condenser |
| D. | feed pump |
| Answer» D. feed pump | |
| 471. |
Which ideal process is carried out at the turbine in vapour power cycle? |
| A. | reversible adiabatic compression |
| B. | reversible adiabatic expansion |
| C. | reversible constant pressure heat addition |
| D. | reversible constant pressure heat rejection |
| Answer» C. reversible constant pressure heat addition | |
| 472. |
The pressure’of a gas in terms of its mean kinetic energy per unit volume E is equal to________________? |
| A. | E/3 |
| B. | E/2 |
| C. | 3E/4 |
| D. | 2E/3 |
| E. | 5E/4 |
| Answer» E. 5E/4 | |
| 473. |
A closed system is one in which_________________________? |
| A. | mass does not cross boundaries of the system, though energy may do so |
| B. | mass crosses the boundary but not the energy |
| C. | neither mass nor energy crosses the boundaries of the system |
| D. | both energy and mass cross the boundaries of the system |
| E. | thermodynamic reactions take place |
| Answer» B. mass crosses the boundary but not the energy | |
| 474. |
According to kinetic theory of gases, the absolute zero temperature is attained when___________________? |
| A. | volume of the gas is zero |
| B. | pressure of the gas is zero |
| C. | kinetic energy of the molecules is zero |
| D. | specific heat of gas is zero |
| E. | mass is zero |
| Answer» D. specific heat of gas is zero | |
| 475. |
Dry air does NOT contain |
| A. | krypton |
| B. | argon |
| C. | neon |
| D. | none of the above |
| Answer» E. | |