Practice Engineering Thermodynamics Multiple Choice Questions Quiz-8 - MCQGeeks.com

Q.1

In an isothermal process,

There is no change in temperature
There is no change in enthalpy
There is no change in internal energy
All of these

Q.2

A cycle consisting of one constant pressure, one constant volume and two isentropic processes is known as

Otto cycle
Stirling cycle
Carnot cycle
Diesel cycle

Q.3

A process, in which the temperature of the working substance remains constant during its expansion or compression, is called

Adiabatic process
Isothermal process
Hyperbolic process
Polytropic process

Q.4

A definite area or a space where some thermodynamic process takes place is known as

Thermodynamic system
Thermodynamic cycle
Thermodynamic process
Thermodynamic law

Q.5

The work ratio of a gas turbine plant is given by

(Net work output)/(Work-done by the turbine)
(Net work output)/(Heat supplied)
(Actual temperature drop)/(Isentropic temperature drop)
(Isentropic increase in temperature)/(Actual increase in temperature)

Q.6

Which is the incorrect statement about Carnot cycle?

All the heat engines are based on Carnot cycle
It is used as the alternate standard of comparison of all heat engines
It provides concept of maximising work output between the two temperature limits
All of the above

Q.7

One kilowatt is equal to

1 N-m/s
100 N-m
1000 N-m/s
1 × 106 N-m/s

Q.8

Which of the following is correct?

Absolute pressure = Gauge pressure + Atmospheric pressure
Gauge pressure = Absolute pressure + Atmospheric pressure
Atmospheric pressure = Absolute pressure + Gauge pressure
Absolute pressure = Gauge pressure - Atmospheric pressure

Q.9

The ideal efficiency of a Brayton cycle without regeneration, with increase in pressure ratio will

Increase
Decrease
Remain unchanged
Increase/decrease depending on application

Q.10

The ratio of molar specific heats for mono-atomic gas is

1
1.4
1.67
1.87

Q.11

When the gas is cooled at constant pressure,

Its temperature increases but volume decreases
Its volume increases but temperature decreases
Both temperature and volume increases
Both temperature and volume decreases

Q.12

Which of the following is correct?

Gauge pressure = Absolute pressure + Atmospheric pressure
Absolute pressure = Gauge pressure + Atmospheric pressure
Absolute pressure = Gauge pressure - Atmospheric pressure
Atmospheric pressure = Absolute pressure + Gauge pressure

Q.13

The specific heat at constant volume is

The amount of heat required to raise the temperature of unit mass of gas through one degree, at constant volume
The amount of heat required to raise the temperature of unit mass of gas through one degree, at constant pressure
The amount of heat required to raise the temperature of 1 kg of water through one degree
Any one of the above

Q.14

Which of the following is the correct statement?

All the reversible engines have the same efficiency.
All the reversible and irreversible engines have the same efficiency.
Irreversible engines have maximum efficiency.
All engines are designed as reversible in order to obtain maximum efficiency.

Q.15

First law of thermodynamics

Enables to determine change in internal energy of the system
Does not enable to determine change in entropy
Provides relationship between heat, work and internal energy
All of the above

Q.16

According to first law of thermodynamics

Work done by a system is equal to heat transferred by the system
Total internal energy of a system during a process remains constant
Internal energy, enthalpy and entropy during a process remain constant
Total energy of a system remains constant

Q.17

Which of the following is the correct statement?

For a given compression ratio, both Otto and Diesel cycles have the same efficiency
For a given compression ratio, Otto cycle is more efficient than Diesel cycle
For a given compression ratio, Diesel cycle is more efficient than Otto cycle
The efficiency of Otto or Diesel cycle has nothing to do with compression ratio

Q.18

According to Clausius statement of second law of thermodynamics

Heat can't be transferred from low temperature source to high temperature source
Heat can be transferred for low temperature to high temperature source by using refrigeration cycle
Heat can be transferred from low temperature to high temperature source if COP of process is more than unity
Heat can't be transferred from low temperature to high temperature source without the aid of external energy

Q.19

The statement that molecular weights of all gases occupy the same volume is known as

Avogadro's hypothesis
Dalton's law
Gas law
Law of thermodynamics

Q.20

In a no flow reversible process for which p = (-3V + 15) × 10⁵ N/m², V changes from 1 m³ to 2 m³. The work done will be about

100 × 10⁵ joules
1 × 10⁵ joules
10 × 10⁵ joules
10 × 10⁵ kilo joules

Q.21

The mass of excess air supplied is equal to

(23/100) × Mass of excess carbon
(23/100) × Mass of excess oxygen
(100/23) × Mass of excess carbon
(100/23) × Mass of excess oxygen

Q.22

Which of the following process can be made reversible with the help of a regenerator?

Constant pressure process
Constant volume process
Constant pvn process
All of these

Q.23

An ideal gas as compared to a real gas at very high pressure occupies

More volume
Less volume
Same volume
Unpredictable behavior

Q.24

The distillation carried out in such a way that the liquid with the lowest boiling point is first evaporated and re-condensed, then the liquid with the next higher boiling point is then evaporated and re-condensed, and so on until all the available liquid fuels are separately recovered in the sequence of their boiling points. Such a process is called

Cracking
Fractional distillation
Full distillation
Carbonisation

Q.25

The value of 1 mm of Hg is equal to

1.333 N/m2
13.33 N/m2
133.3 N/m2
1333 N/m2

Q.26

The efficiency of Joule cycle is

Less than Carnot cycle
Equal to Carnot cycle
Greater than Carnot cycle
None of these

Q.27

If the value of n = 0 in the equation pvn = C, then the process is called

Constant volume process
Adiabatic process
Constant pressure process
Isothermal process

Q.28

If in the equation pvn = C, the value of n = ∝, then the process is called

Constant volume process
Adiabatic process
Constant pressure process
Isothermal process

Q.29

If a gas vapour is allowed to expand through a very minute aperture, then such a process is known as

Free expansion
Hyperbolic expansion
Adiabatic expansion
Throttling

Q.30

In an irreversible process, there is a

No loss of heat
Loss of heat
Gain of heat
No gain of heat

0 h : 0 m : 1 s