MCQOPTIONS
Saved Bookmarks
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.
| 1. |
When two bodies are in thermal equilibrium with a third body they are also in thermal equilibrium with each other. 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 | |
| 2. |
The value of one bar (in SI units) is equal to |
| A. | 100 n/m?? |
| B. | 1000 n/m?? |
| C. | 1??10 n/m?? |
| D. | 1??10 n/m?? |
| Answer» E. | |
| 3. |
A series of operations, which take place in a certain order & restore the initial condition is known as |
| A. | reversible cycle |
| B. | irreversible cycle |
| C. | thermodynamic cycle |
| D. | none of the above |
| Answer» D. none of the above | |
| 4. |
During an adiabatic compression when temperature increase by 100% the pressure increases by 1000%. The ratio of specific heats, ? is |
| A. | 1.3 |
| B. | 1.35 |
| C. | 1.4 |
| D. | 1.45 |
| Answer» D. 1.45 | |
| 5. |
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 pressure is |
| A. | 10% w |
| B. | 12 % w |
| C. | 15% w |
| D. | 20% w |
| Answer» D. 20% w | |
| 6. |
Entropy at absolute zero temperature is zero for a |
| A. | perfect gas |
| B. | perfect substance |
| C. | perfect crystal |
| D. | glass |
| Answer» D. glass | |
| 7. |
1.6 Kg of air is expanded at constant pressure from 100 C to 0 C resulting in entropy change of - 2.0 J/K 3.2 Kg of air is cooled at constant volume from 100 C to 0 C with a change in entropy of -3.0 J/K. The ratio Cp/ Cv is |
| A. | 1.333 |
| B. | 1.366 |
| C. | 1.4 |
| D. | 1.43 |
| Answer» D. 1.43 | |
| 8. |
During a polytropic expansion work obtained is 1.8 times the heat transferred. If ?=1.4, n will be |
| A. | 1.2 |
| B. | 1.19 |
| C. | 1.178 |
| D. | 1.155 |
| Answer» E. | |
| 9. |
Average temp.at which heat is supplied is increased in |
| A. | simple rankine cycle |
| B. | reheat rankine cycle |
| C. | regenerative rankine cycle |
| D. | modified rankine cycle |
| Answer» D. modified rankine cycle | |
| 10. |
Entropy of mixture of two gases after sudden mixing is |
| A. | greater than |
| B. | less than its inputtemperature |
| C. | same as sum of entropy ofindividual gases |
| D. | unpredictable |
| Answer» B. less than its inputtemperature | |
| 11. |
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 | |
| 12. |
A sequence of operations which a gas undergoes in such a way that final state is same as original state, mahe a |
| A. | reversible cycle |
| B. | irreversible cycle |
| C. | thermal cycle |
| D. | thermodynamic cycle |
| Answer» E. | |
| 13. |
A perfect gas having p1= 0.1 M/mm , v1=0.18 m , T1=20 C is compressed to 1/10 of volume in an isothermal process. The change in entropy is |
| A. | -141.45 j/k |
| B. | 141.45 j/k |
| C. | -41446.23 j/k |
| D. | 0 |
| Answer» C. -41446.23 j/k | |
| 14. |
The extension & compression of a helical spring is an example of |
| A. | irreversible process |
| B. | reversible process |
| C. | isothermal process |
| D. | adiabatic process |
| Answer» C. isothermal process | |
| 15. |
Which statement is wrong for throttling expansion |
| A. | pressure drop = 0 |
| B. | change in enthalpy = 0 |
| C. | work done = 0 |
| D. | change in internalenergy = 0 |
| Answer» D. change in internalenergy = 0 | |
| 16. |
Which statement is wrong for adiabatic expansion |
| A. | h = 0 |
| B. | w = 0 |
| C. | ds = 0 |
| D. | w+e = 0 |
| Answer» E. | |
| 17. |
Under which of the following conditions all gases behave ideally? |
| A. | high pressure conditions |
| B. | law pressure conditions |
| C. | vaccum conditions |
| D. | all of the aboveconditions |
| Answer» C. vaccum conditions | |
| 18. |
Internal energy & enthalpy of an ideal gas are functions of |
| A. | pressure only |
| B. | temperature only |
| C. | specific volume only |
| D. | temperature & pressure |
| Answer» C. specific volume only | |
| 19. |
When two gases suddenly mix up with each other then resultant entropy of the system will |
| A. | remain unaltered |
| B. | decrease |
| C. | increase |
| D. | becomes zero |
| Answer» D. becomes zero | |
| 20. |
On which of the following factors does air standard efficiency of a diesel cycle depend? |
| A. | adiabatic compression ratio |
| B. | ratio of specific heats |
| C. | cut-off ratio |
| D. | all of the above |
| Answer» E. | |
| 21. |
Which of the following processes is reversible process? |
| A. | throttling |
| B. | adiabatic |
| C. | isothermal |
| D. | none of the above |
| Answer» B. adiabatic | |
| 22. |
Which of the following processes are reversible processes? |
| A. | isothermal & adiabatic |
| B. | constant volume &constant pressure |
| C. | hyperbolic & pv?= constant |
| D. | none of the above |
| Answer» B. constant volume &constant pressure | |
| 23. |
Adiabatic & isothermal processes are identical at |
| A. | absolute zerotemperature |
| B. | below 0 c temperature |
| C. | saturation temperature |
| D. | critical temperature |
| Answer» B. below 0 c temperature | |
| 24. |
In polytropic process pv?=C the value of exponent n= ? is indicative of |
| A. | isobaric process |
| B. | isentropic process |
| C. | isochoric process |
| D. | throttling process |
| Answer» D. throttling process | |
| 25. |
Entropy in statistical thermodynamics is defined as |
| A. | a universal property |
| B. | reversible heat transfer |
| C. | degree of randomness |
| D. | measure of reversibilityof a system |
| Answer» D. measure of reversibilityof a system | |
| 26. |
Which one of the following pairs best expresses a relationship similar to that expressed in the pair 'pressure-volume' for a thermodynamic system undergoing a process? |
| A. | enthalpy-entropy |
| B. | pressure-enthalpy |
| C. | pressure-temperature |
| D. | temperature-entropy |
| Answer» E. | |
| 27. |
A mixture of gases expands from 0.03 m to 0.06 m at a constant pressure of 1 Mpa & absorbs 84 kJ of heat during the process. The change in internal energy of the mixture is |
| A. | 30 kj |
| B. | 54 kj |
| C. | 84 kj |
| D. | 114 kj |
| Answer» C. 84 kj | |
| 28. |
Variations of pressure & volume at constant temperature are correlated through |
| A. | charle's law |
| B. | boyle's law |
| C. | gas law |
| D. | gay lussac's law |
| Answer» C. gas law | |
| 29. |
The relationship between pressure & volume is expressed as pv?=const. Select wrong statement |
| A. | expansion with n=0 is a constant pressure process |
| B. | expansion with n=? is an adiabatic process |
| C. | expansion with n=? is not possible |
| D. | expansion at constant temperature has n=1 |
| Answer» D. expansion at constant temperature has n=1 | |
| 30. |
Air expands from initial condition of p1, v1 to final condition of 1/2 p1, 2v1. Choose the correct statement |
| A. | no work is performed during expansion |
| B. | expansion is isothermal |
| C. | expansion is polytropic with n= 1.2 |
| D. | expansion is adiabatic |
| Answer» D. expansion is adiabatic | |
| 31. |
The amount of heat absorbed by a system at lower temperature is |
| A. | coeff. of performance |
| B. | efficiency |
| C. | work supplied |
| D. | refrigerating effect |
| Answer» D. refrigerating effect | |
| 32. |
Boyle's law states that, when tempearture is constant, the volume of a given 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 | |
| 33. |
. Is one in which neither any heat enters nor leaves the system |
| A. | isochoric process |
| B. | isobaric process |
| C. | isentropic process |
| D. | isothermal process |
| Answer» D. isothermal process | |
| 34. |
. Law states that equal volume of all gases, at the same temperature & pressure, contains equal number of molecules |
| A. | boyle's |
| B. | gay-lussac |
| C. | avogadro |
| D. | charle's |
| Answer» D. charle's | |
| 35. |
The change of entropy is considered to be when heat is absorbed by the gas |
| A. | positive |
| B. | negative |
| C. | zero |
| D. | none of the above |
| Answer» B. negative | |
| 36. |
In which of the following processes the change in internal energy of a gas is equal to the work done |
| A. | adiabatic process |
| B. | isothermal process |
| C. | constant volume process |
| D. | constant pressure process |
| Answer» B. isothermal process | |
| 37. |
In a Carnot cycle which of the following processez 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 | |
| 38. |
In the case of real gases, cp will be equal to cv |
| A. | at absolute zero |
| B. | at triple point |
| C. | at critical temperature |
| D. | above criticaltempeature |
| Answer» B. at triple point | |
| 39. |
Universal gas constant is defined as equal to the product of the molecular weight of the gas & |
| A. | gas constant |
| B. | specific heat at constant volume |
| C. | specific heat a constant pressure |
| D. | ratio of two specific heats |
| Answer» B. specific heat at constant volume | |
| 40. |
The physical properties of a perfect gas are controlled by which of the following variables? |
| A. | volume |
| B. | temperature |
| C. | pressure |
| D. | all of the above |
| Answer» E. | |
| 41. |
All engineering process, strictly speaking are |
| A. | reversible cycle |
| B. | irreversible |
| C. | quasti-static |
| D. | thermodynamically inequillibrium |
| Answer» E. | |
| 42. |
Change of entropy depends upon which of 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 | |
| 43. |
Isothermal, isobaric, isochoric & adiabatic processes, under ideal conditions, are . Processes |
| A. | thermodynamic |
| B. | stable |
| C. | dynamic |
| D. | quasi-static |
| Answer» E. | |
| 44. |
In a reversible adiabatic process head added is equal to |
| A. | zero |
| B. | positive value |
| Answer» B. positive value | |
| 45. |
Which one of the following processes or systems does not involve heat |
| A. | steady processes |
| B. | isothermal processes |
| C. | adiabatic processes |
| D. | thermal processes |
| Answer» D. thermal processes | |
| 46. |
An inventor claims that a new heat cycle will develop 0.4 kW for a heat addition of 32.5 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 | |
| 47. |
In the polytropic process equation pv = constant, if n is infinitely large, the process is termed as |
| A. | constant volume |
| B. | constant pressure |
| C. | constant temperature |
| D. | diabatic |
| Answer» B. constant pressure | |
| 48. |
For a reversible adiabatic process, the change in entropy is |
| A. | zero |
| B. | minimum |
| C. | maximum |
| D. | infinite |
| Answer» B. minimum | |
| 49. |
The property of a working substance which increases or decreases as the heat is supplied or removed in a reversible manner is known as |
| A. | enthalpy |
| B. | internal energy |
| C. | entropy |
| D. | external energy |
| Answer» D. external energy | |
| 50. |
The change of entropy when heat is absorbed by the gas is |
| A. | positive |
| B. | negative |
| C. | positive or negative |
| D. | all of the above |
| Answer» B. negative | |