Which of the following statement is correct?
The heat and work are boundary phenomena
The heat and work represent the energy crossing the boundary of the system
The heat and work are path functions
All of the above
Correct Answer :
D. All of the above
Related Questions
For the constant pressure and heat input, the air standard efficiency of gas power cycle is in the order
Dual cycle, Diesel cycle, Otto cycle
Otto cycle, Diesel cycle, Dual cycle
Dual cycle, Otto cycle, Diesel cycle
Diesel cycle, Otto cycle, Dual cycle
When coal is first dried and then crushed to a fine powder by pulverising machine, the resulting fuel is called
Wood charcoal
Bituminous coal
Briquetted coal
None of these
A beam which is fixed at one end and free at the other is called
Simply supported beam
Fixed beam
Overhanging beam
Cantilever beam
For the same compression ratio, the efficiency of Diesel cycle is __________ Otto cycle.
Greater than
Less than
Equal to
None of these
The ideal efficiency of a Brayton cycle with regeneration, with increase in pressure ratio will
Increase
Decrease
Remain unchanged
Increase/decrease depending on application
The intensity of stress which causes unit strain is called
Unit mass
Modulus of rigidity
Bulk modulus
Modulus of Elasticity
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
The principal constituents of a fuel are
Carbon and hydrogen
Oxygen and hydrogen
Sulphur and oxygen
Sulphur and hydrogen
A body is subjected to a direct tensile stress of 300 MPa in one plane accompanied by a simple shear stress of 200 MPa. The maximum shear stress will be
-100 MPa
250 MPa
300 MPa
400 MPa
The ultimate analysis of coal consists of the determination of the percentage of
Carbon
Hydrogen and nitrogen
Sulphur and ash
All of these
For riveting, the size of hole drilled in plates is __________ shank diameter of rivet.
Equal to
Less than
Greater than
None of these
In an ideal gas turbine plant, it is assumed that the compression and expansion processes are
Isothermal
Isentropic
Polytropic
None of these
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 pressure
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 1 kg of water through one degree
Any one of the above
The absolute zero temperature is taken as
237°C
-273°C
-237°C
273°C
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.
The entropy of water at 0°C is assumed to be
1
0
-1
10
Relation between cp and cv is given by (where cp = Specific heat at constant pressure, cv = Specific heat at constant volume, γ = cp/cv, known as adiabatic index, and R = Gas constant)
cv/ cp =R
cp - cv = R
cv = R/ γ-1
Both (B) and (C)
The variables which control the physical properties of a perfect gas are
Pressure exerted by the gas
Volume occupied by the gas
Temperature of the gas
All of these
The energy stored in a body when strained within elastic limit is known as
Resilience
Proof resilience
Strain energy
Impact energy
The efficiency and work ratio of a simple gas turbine cycle are
Very low
Low
High
Very high
The change of entropy, when heat is absorbed by the gas, is
Positive
Negative
Positive or negative
None of these
The efficiency of the dual combustion cycle for the same compression ratio is __________ Diesel cycle.
Greater than
Less than
Equal to
None of these
Proof resilience per material is known as
Resilience
Proof resilience
Modulus of resilience
Toughness
The efficiency of Diesel cycle depends upon
Temperature limits
Pressure ratio
Compression ratio
Cut-off ratio and compression ratio
The strain energy stored in a body due to suddenly applied load compared to when it is applied gradually is
Same
Twice
Four times
Eight times
The extension of a circular bar tapering uniformly from diameter d₁ at one end to diameter d₂ at the other end and subjected to an axial pull of P is given by
δl = 4PE/ πl²
δl = 4πld²/PE
δl = 4Pl/πEd₁d₂
δl = 4PlE/ πd₁d₂
Stirling and Ericsson cycles are
Reversible cycles
Irreversible cycles
Semi-reversible cycles
Adiabatic irreversible cycles
The following cycle is used for air craft refrigeration
Brayton cycle
Joule cycle
Carnot cycle
Reversed Brayton cycle
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
When a perfect gas is expanded through an aperture of minute dimensions, the process is known as
Isothermal process
Adiabatic process
Free expansion process
Throttling process