The gas turbine cycle with regenerator improves
Thermal efficiency
Work ratio
Avoids pollution
None of these
Correct Answer :
A. Thermal efficiency
Related Questions
The behaviour of super-heated vapour is similar to that of
Perfect gas
Air
Steam
Ordinary gas
In a free expansion process,
W1 - 2 = 0
Q1 - 2 = 0
dU = 0
All of these
A cycle consisting of __________ and two isothermal processes is known as Stirling cycle.
Two constant pressure
Two constant volume
Two isentropic
One constant pressure, one constant volume
For riveting, the size of hole drilled in plates is __________ shank diameter of rivet.
Equal to
Less than
Greater than
None of these
Petrol is distilled at
65° to 220°C
220° to 345°C
345° to 470°C
470° to 550°C
The pressure exerted by an ideal gas is ________ of the kinetic energy of all the molecules contained in a unit volume of gas.
One-half
One-third
Two-third
Three-fourth
If percentage reduction in area of a certain specimen made of material 'A' under tensile test is 60% and the percentage reduction in area of a specimen with same dimensions made of material 'B' is 40%, then
The material A is more ductile than material B
The material B is more ductile than material A
The ductility of material A and B is equal
The material A is brittle and material B is ductile
High air-fuel ratio in gas turbines
Increases power output
Improves thermal efficiency
Reduces exhaust temperature
Do not damage turbine blades
The heat and work are mutually convertible. This statement is called __________ law of thermodynamics.
Zeroth
First
Second
Third
The sum of internal energy (U) and the product of pressure and volume (p.v) is known as
Workdone
Entropy
Enthalpy
None of these
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
When gas is heated at constant pressure, the heat supplied is utilised in
Increasing the internal energy of gas
Doing some external work
Increasing the internal energy of gas and also for doing some external work
None of the above
The intensity of stress which causes unit strain is called
Unit mass
Modulus of rigidity
Bulk modulus
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
During which of the following process does heat rejection takes place in Carnot cycle?
Isothermal expansion
Isentropic expansion
Isothermal compression
Isentropic compression
The tensile strength of the welded joint for double fillet is (where s = Leg or size of the weld, l = Length of weld, and σt = Allowable tensile stress for weld metal)
0.5 s.l.σt
s.l.σt
√2 s.l.σt
2.s.l.σt
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
A coil is cut into two halves, the stiffness of cut coil will be
Double
Half
Same
None of these
Two shafts 'A' and 'B' transmit the same power. The speed of shaft 'A' is 250 r.p.m. and that of shaft 'B' is 300 r.p.m.
The shaft 'B' has the greater diameter
The shaft 'A' has the greater diameter
Both are of same diameter
None of these
The value of cp/cv for air is
1
1.4
1.45
2.3
The strain energy stored in a solid circular shaft subjected to shear stress (τ), is: (Where G = Modulus of rigidity for the shaft material)
τ²/ 2G × Volume of shaft
τ/ 2G × Volume of shaft
τ²/ 4G × Volume of shaft
τ/ 4G × Volume of shaft
A beam is loaded as cantilever. If the load at the end is increased, the failure will occur
In the middle
At the tip below the load
At the support
Anywhere
One Joule (J) is equal to
1 N-m
1 kN-m
10 N-m/s
10 kN-m/s
The heating of a gas at constant pressure is governed by
Boyle's law
Charles' law
Gay-Lussac law
Avogadro's law
The stress induced in a body due to suddenly applied load compared to when it is applied gradually is
Same
Half
Two times
Four times
The deformation of a bar under its own weight compared to the deformation of same body subjected to a direct load equal to weight of the body is
Same
Double
Half
Four times
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
According to Avogadro's law
The product of the gas constant and the molecular mass of an ideal gas is constant
The sum of partial pressure of the mixture of two gases is sum of the two
Equal volumes of all gases, at the same temperature and pressure, contain equal number of molecules
All of the above
The ultimate tensile stress of mild steel compared to ultimate compressive stress is
Same
More
Less
Unpredictable
The efficiency of Diesel cycle with decrease in cut-off
Increases
Decreases
First increases and then decreases
First decreases and then increases