The condition for the reversibility of a cycle is
The pressure and temperature of the working substance must not differ, appreciably, from those of the surroundings at any stage in the process
All the processes, taking place in the cycle of operation, must be extremely slow
The working parts of the engine must be friction free
All of the above
Correct Answer :
D. All of the above
Related Questions
An open cycle gas turbine works on
Carnot cycle
Otto cycle
Joule's cycle
Stirling cycle
For a simply supported beam of length l, when a concentrated load W is applied in the centre of the beam, the maximum deflection is
5WL³/ 384EI
WL³/384EI
WL³/ 348EI
WL³/ 48EI
The gas constant (R) is equal to the
Sum of two specific heats
Difference of two specific heats
Product of two specific heats
Ratio of two specific heats
For which material the Poisson's ratio is more than unity
Steel
Copper
Aluminium
None of the above
The distance between the centres of the rivets in adjacent rows of zigzag riveted joint is known as
Pitch
Back pitch
Diagonal pitch
Diametric pitch
When the gas is heated at constant pressure, the heat supplied
Increases the internal energy of the gas
Increases the temperature of the gas
Does some external work during expansion
Both (B) and (C)
A shaft revolving at ω rad/s transmits torque (T) in Nm. The power developed is
T.ω watts
2π. T.ω watts
2π. T.ω/75 watts
2π. T.ω/4500 watts
The state of a substance whose evaporation from its liquid state is complete, is known as
Vapour
Perfect gas
Air
Steam
The neutral axis of the cross-section a beam is that axis at which the bending stress is
Zero
Minimum
Maximum
Infinity
A riveted joint in which the number otrivets decrease from innermost to outer most rows is called
Chain riveted joint
Diamond riveted joint
Crisscross riveted joint
Zigzag riveted joint
When a bar is subjected to a change of temperature and its deformation is prevented, the stress induced in the bar is
Tensile stress
Compressive stress
Shear stress
Thermal stress
The isothermal and adiabatic processes are regarded as
Reversible process
Irreversible process
Reversible or irreversible process
None of these
Energy can neither be created nor destroyed, but it can be transformed from one form to another. This statement is known as
Zeroth law of thermodynamics
First law of thermodynamics
Second law of thermodynamics
Kinetic theory of gases
The amount of heat required to raise the temperature of __________ water through one degree is called kilojoules.
1 g
10 g
100 g
1000 g
If the radius of wire stretched by a load is doubled, then its Youngs modulus will be
Doubled
Halved
Becomes four times
None of the above
The buckling load for a given material depends on
Slenderness ratio and area of cross-section
Poisson's ratio and modulus of elasticity
Slenderness ratio and modulus of elasticity
Slenderness ratio, area of cross-section and modulus of elasticity
According to Kelvin-Planck's statement of second law of thermodynamics,
It is impossible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work
It is possible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work
It is impossible to construct a device which operates in a cyclic process and produces no effect other than the transfer of heat from a cold body to a hot body
None of the above
The processes occuring in open system which permit the transfer of mass to and from the system, are known as
Flow processes
Non-flow processes
Adiabatic processes
None of these
When a body is subjected to two equal and opposite pushes, as a result of which the body tends to reduce its length, then
The stress and strain induced is compressive
The stress and strain induced is tensile
Both A and B is correct
None of these
According to First law of thermodynamics,
Total internal energy of a system during a process remains constant
Total energy of a system remains constant
Workdone by a system is equal to the heat transferred by the system
Internal energy, enthalpy and entropy during a process remain constant
Slenderness of a column is zero when
Ends are firmly fixed
Column is supported on all sides throughout the length
Length is equal to radius of gyration
Length is twice the radius of gyration
The value of modulus of elasticity for mild steel is of the order of
2.1 × 10⁵ kg/cm²
2.1 × 10⁶ kg/cm²
2.1 × 10⁷ kg/cm²
0.1 × 10⁶ kg/cm²
A beam which is fixed at one end and free at the other is called
Simply supported beam
Fixed beam
Overhanging beam
Cantilever beam
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
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
The expansion ratio (r) is the ratio of (where v1 = Volume at the beginning of expansion, and v2 = Volume at the end of expansion)
v1/v2
v2/v1
(v1 + v2)/v1
(v1 + v2)/v2
The value of specific heat at constant pressure (cp) is __________ that of at constant volume (cv).
Less than
Equal to
More than
None of these
Brayton cycle consists' of following four processes
Two isothermals and two isentropic
Two isentropic and two constant volumes
Two isentropic, one constant volume and one constant pressure
Two isentropic and two constant pressures
According to Avogadro's law, the density of any two gases is __________ their molecular masses, if the gases are at the same temperature and pressure.
Equal to
Directly proportional to
Inversely proportional to
None of these
Which of the following statement is wrong?
The closed cycle gas turbine plants are external combustion plants.
In the closed cycle gas turbine, the pressure range depends upon the atmospheric pressure.
The advantage of efficient internal combustion is eliminated as the closed cycle has an external surface.
In open cycle gas turbine, atmosphere acts as a sink and no coolant is required.