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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.
| 601. |
According to First law of thermodynamics, |
| A. | Total internal energy of a system during a process remains constant |
| B. | Total energy of a system remains constant |
| C. | Work-done by a system is equal to the heat transferred by the system |
| D. | Internal energy, enthalpy and entropy during a process remain constant |
| Answer» C. Work-done by a system is equal to the heat transferred by the system | |
| 602. |
Work-done during adiabatic expansion is given by (where p1 v1, T1 = Pressure, volume and temperature for the initial condition of gas, p2, v2, T2 = Corresponding values for the final condition of gas, R = Gas constant, and γ = Ratio of specific heats) |
| A. | (p1 v1 - p2, v2)/(γ - 1) |
| B. | [m R (T1 - T2)] /(γ - 1) |
| C. | [m R T1/(γ - 1)][1 - (p2, v2 /p1 v1)] |
| D. | All of these |
| Answer» E. | |
| 603. |
The air standard efficiency of an Otto cycle is given by (where r = Compression ratio, and γ = Ratio of specific heats) |
| A. | 1 - rγ - 1 |
| B. | 1 + rγ - 1 |
| C. | 1 - (1/ rγ - 1) |
| D. | 1 + (1/ rγ - 1) |
| Answer» D. 1 + (1/ rγ - 1) | |
| 604. |
If a certain amount of dry ice is mixed with same amount of water at 80°C, the final temperature of mixture will be |
| A. | 80°C |
| B. | 0°C |
| C. | 40°C |
| D. | 20°C |
| Answer» C. 40°C | |
| 605. |
One kg of carbon produces ________ kg of carbon dioxide. |
| A. | 3/7 |
| B. | 11/7 |
| C. | 11/3 |
| D. | 4/11 |
| Answer» D. 4/11 | |
| 606. |
The ratio of two specific heats of air is equal to |
| A. | 0.17 |
| B. | 0.24 |
| C. | 0.1 |
| D. | 1.41 |
| Answer» E. | |
| 607. |
In a free expansion process |
| A. | Work done is zero |
| B. | Heat transfer is zero |
| C. | Both (A) and (B) above |
| D. | Work done is zero but heat increases |
| Answer» D. Work done is zero but heat increases | |
| 608. |
When cut-off ratio is ________; the efficiency of Diesel cycle approaches to Otto cycle efficiency |
| A. | 1/4 |
| B. | Zero |
| C. | 1/5 |
| D. | 2 |
| Answer» C. 1/5 | |
| 609. |
The value of cp/cv for air is |
| A. | 1 |
| B. | 1.4 |
| C. | 1.45 |
| D. | 2.3 |
| Answer» C. 1.45 | |
| 610. |
Carbonization of coal consists of |
| A. | Drying and crushing the coal to a fine powder |
| B. | Moulding the finely ground coal under pressure with or without a binding material |
| C. | Heating the wood with a limited supply of air to temperature not less than 280°C |
| D. | None of the above |
| Answer» E. | |
| 611. |
Which of the following gas has the highest calorific value? |
| A. | Coal gas |
| B. | Producer gas |
| C. | Mond gas |
| D. | Blast furnace gas |
| Answer» B. Producer gas | |
| 612. |
The ideal efficiency of a Brayton cycle without regeneration, with increase in pressure ratio will |
| A. | Increase |
| B. | Decrease |
| C. | Remain unchanged |
| D. | Increase/decrease depending on application |
| Answer» B. Decrease | |
| 613. |
A process, in which the temperature of the working substance remains constant during its expansion or compression, is called |
| A. | Adiabatic process |
| B. | Isothermal process |
| C. | Hyperbolic process |
| D. | Polytropic process |
| Answer» C. Hyperbolic process | |
| 614. |
A cycle consisting of one constant pressure, one constant volume and two isentropic processes is known as |
| A. | Otto cycle |
| B. | Stirling cycle |
| C. | Carnot cycle |
| D. | Diesel cycle |
| Answer» E. | |
| 615. |
In a steady flow process, the ratio of |
| A. | Heat transfer is constant |
| B. | Work transfer is constant |
| C. | Mass flow at inlet and outlet is same |
| D. | All of these |
| Answer» E. | |
| 616. |
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 |
| Answer» D. Boyle's Law | |
| 617. |
The efficiency of a Carnot engine depends on |
| A. | Working substance |
| B. | Design of engine |
| C. | Size of engine |
| D. | Temperatures of source and sink |
| Answer» E. | |
| 618. |
The gas turbine cycle with regenerator improves |
| A. | Work ratio |
| B. | Thermal efficiency |
| C. | Avoid pollution |
| D. | None of these |
| Answer» C. Avoid pollution | |
| 619. |
Energy can neither be created nor destroyed, but it can be transformed from one form to another. This statement is known as |
| A. | Zeroth law of thermodynamics |
| B. | First law of thermodynamics |
| C. | Second law of thermodynamics |
| D. | Kinetic theory of gases |
| Answer» C. Second law of thermodynamics | |
| 620. |
The heat flows from a cold body to a hot body with the aid of an external source. This statement is given by |
| A. | Kelvin |
| B. | Joule |
| C. | Clausis |
| D. | Gay-Lussac |
| Answer» D. Gay-Lussac | |
| 621. |
When gas is heated at constant pressure, the heat supplied is utilized in |
| A. | Increasing the internal energy of gas |
| B. | Doing some external work |
| C. | Increasing the internal energy of gas and also for doing some external work |
| D. | None of the above |
| Answer» D. None of the above | |
| 622. |
The change of entropy, when heat is absorbed by the gas, is |
| A. | Positive |
| B. | Negative |
| C. | Positive or negative |
| D. | None of these |
| Answer» B. Negative | |
| 623. |
Select the wrong statement |
| A. | A Joule cycle consists of two constant volume and two isentropic processes. |
| B. | An Otto cycle consists of two constant volume and two isentropic processes. |
| C. | An Ericsson cycle consists of two constant pressure and two isothermal processes. |
| D. | All of the above |
| Answer» B. An Otto cycle consists of two constant volume and two isentropic processes. | |
| 624. |
Kerosene is distilled at |
| A. | 65° to 220°C |
| B. | 220° to 345°C |
| C. | 345° to 470°C |
| D. | 470° to 550°C |
| Answer» C. 345° to 470°C | |
| 625. |
Calorie is a measure of |
| A. | Specific heat |
| B. | Quantity of heat |
| C. | Thermal capacity |
| D. | Entropy |
| Answer» C. Thermal capacity | |
| 626. |
In an isothermal process, the internal energy |
| A. | Increases |
| B. | Decreases |
| C. | Remain constant |
| D. | First increases and then decreases |
| Answer» D. First increases and then decreases | |
| 627. |
The efficiency of the Carnot cycle is (where T1 and T2 = Highest and lowest temperature during the cycle) |
| A. | (T1/T2) - 1 |
| B. | 1 - (T1/T2) |
| C. | 1 - (T2/T1) |
| D. | 1 + (T2/T1) |
| Answer» D. 1 + (T2/T1) | |
| 628. |
The compression ratio for Diesel engines is |
| A. | 15 to 20 |
| B. | 5 to 8 |
| C. | 3 to 6 |
| D. | 20 to 30 |
| Answer» B. 5 to 8 | |
| 629. |
If both Stirling and Carnot cycles operate within the same temperature limits, then efficiency of Stirling cycle as compared to Carnot cycle |
| A. | More |
| B. | Less |
| C. | Equal |
| D. | Depends on other factors |
| Answer» D. Depends on other factors | |
| 630. |
The efficiency of Diesel cycle approaches to Otto cycle efficiency when |
| A. | Cut-off is decreased |
| B. | Cut-off is constant |
| C. | Cut-off is increased |
| D. | Cut-off is zero |
| Answer» C. Cut-off is increased | |
| 631. |
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 |
| Answer» E. | |
| 632. |
The entropy __________ in an irreversible cyclic process. |
| A. | Remains constant |
| B. | Decreases |
| C. | Increases |
| D. | None of these |
| Answer» D. None of these | |
| 633. |
When cut-off ratio is __________ the efficiency of Diesel cycle approaches to Otto cycle efficiency. |
| A. | Zero |
| B. | 1/5 |
| C. | 4/5 |
| D. | 1 |
| Answer» B. 1/5 | |
| 634. |
Carnot cycle consists of |
| A. | Two constant volume and two isentropic processes |
| B. | Two isothermal and two isentropic processes |
| C. | Two constant pressure and two isentropic processes |
| D. | One constant volume, one constant pressure and two isentropic processes |
| Answer» C. Two constant pressure and two isentropic processes | |
| 635. |
Stirling cycle consists of |
| A. | Two constant volume and two isentropic processes |
| B. | Two constant volume and two isothermal processes |
| C. | Two constant pressure and two isothermal processes |
| D. | One constant volume, one constant pressure and two isentropic processes |
| Answer» C. Two constant pressure and two isothermal processes | |
| 636. |
When a gas is heated at constant pressure |
| A. | Its temperature will increase |
| B. | Its volume will increase |
| C. | Both temperature and volume will increase |
| D. | Neither temperature not volume will increase |
| Answer» D. Neither temperature not volume will increase | |
| 637. |
Coke is produced |
| A. | When coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel |
| B. | From the finely ground coal by moulding under pressure with or without a binding material |
| C. | When coal is first dried and then crushed to a fine powder by pulverizing machine |
| D. | By heating wood with a limited supply of air to a temperature not less than 280°C |
| Answer» B. From the finely ground coal by moulding under pressure with or without a binding material | |
| 638. |
Entropy change depends on |
| A. | Heat transfer |
| B. | Mass transfer |
| C. | Change of temperature |
| D. | Thermodynamic state |
| Answer» B. Mass transfer | |
| 639. |
One molecule of oxygen consists of __________ atoms of oxygen. |
| A. | 2 |
| B. | 4 |
| C. | 8 |
| D. | 16 |
| Answer» B. 4 | |
| 640. |
A molecule consisting of one atom is known as |
| A. | Mono-atomic |
| B. | Di-atomic |
| C. | Tri-atomic |
| D. | Poly-atomic |
| Answer» B. Di-atomic | |
| 641. |
The entropy may be expressed as a function of |
| A. | Pressure and temperature |
| B. | Temperature and volume |
| C. | Heat and work |
| D. | All of these |
| Answer» B. Temperature and volume | |
| 642. |
Mixture of ice and water form a |
| A. | Closed system |
| B. | Open system |
| C. | Isolated system |
| D. | Heterogeneous system |
| Answer» E. | |
| 643. |
For a thermodynamic process to be reversible, the temperature difference between hot body and working substance should be |
| A. | Zero |
| B. | Minimum |
| C. | Maximum |
| D. | Infinity |
| Answer» B. Minimum | |
| 644. |
One kg of carbon requires 4/3 kg of oxygen and produces __________ kg of carbon monoxide gas. |
| A. | 8/3 |
| B. | 11/3 |
| C. | 11/7 |
| D. | 7/3 |
| Answer» E. | |
| 645. |
One kg of carbon requires 4/3 kg of oxygen and produces ________ kg of carbon monoxide gas. |
| A. | 8/3 |
| B. | 7/3 |
| C. | 11/7 |
| D. | 11/3 |
| Answer» C. 11/7 | |
| 646. |
The process is adiabatic, if the value of n in the equation pvn = C, is |
| A. | Zero |
| B. | One |
| C. | γ |
| D. | ∝ |
| Answer» D. ∝ | |
| 647. |
A process of heating crude oil to a high temperature under a very high pressure to increase the yield of lighter distillates, is known as |
| A. | Cracking |
| B. | Carbonization |
| C. | Fractional distillation |
| D. | Full distillation |
| Answer» B. Carbonization | |
| 648. |
All perfect gases change in volume by 1/273th of its original volume at 0°C for every 1°C change in temperature, when the pressure remains constant. This statement is called |
| A. | Boyle's law |
| B. | Charles' law |
| C. | Gay-Lussac law |
| D. | Joule's law |
| Answer» C. Gay-Lussac law | |
| 649. |
The absolute zero temperature is taken as |
| A. | 237°C |
| B. | -273°C |
| C. | -237°C |
| D. | 273°C |
| Answer» C. -237°C | |
| 650. |
The basis for measuring thermodynamic property of temperature is given by |
| A. | Zeroth law of thermodynamics |
| B. | First law of thermodynamics |
| C. | Second law of thermodynamics |
| D. | Third law of thermodynamics |
| Answer» B. First law of thermodynamics | |