The ideal efficiency of a Brayton cycle without regeneration, with increase in pressure ratio will
Increase
Decrease
Remain unchanged
Increase/decrease depending on application
Correct Answer :
A. Increase
Related Questions
The state of stress at a point in a loaded member is shown in the below figure. The magnitude of maximum shear stress is
10 MPa
30 MPa
50 MPa
100 MPa
According to Euler's column theory, the crippling load for a column of length (l) with one end fixed and the other end free is __________ the crippling load for a similar column hinged at both the ends.
Equal to
Less than
More than
None of these
The hyperbolic process is governed by
Boyle's law
Charles' law
Gay-Lussac law
Avogadro's law
A body is subjected to a tensile stress of 1200 MPa on one plane and another tensile stress of 600 MPa on a plane at right angles to the former. It is also subjected to a shear stress of 400 MPa on the same planes. The maximum normal stress will be
400 MPa
500 MPa
900 MPa
1400 MPa
A concentrated load is one which
Acts at a point on a beam
Spreads non-uniformly over the whole length of a beam
Spreads uniformly over the whole length of a beam
Varies uniformly over the whole length of a beam
Which of the following gas has a minimum molecular mass?
Oxygen
Nitrogen
Hydrogen
Methane
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
The ratio of specific heat at constant pressure (cp) and specific heat at constant volume (cv) is always __________ one.
Equal to
Less than
Greater than
None of these
The efficiency and work ratio of a simple gas turbine cycle are
Very low
Low
High
Very high
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 polytropic index (n) is given by
log (p1p2)/log (v1v2)
log (p2/ p1)/log (v1/ v2)
log (v1/ v2)/ log (p1/p2)
log [(p1v1)/(p2v2)]
The materials which exhibit the same elastic properties in all directions are called
Homogeneous
Inelastic
Isotropic
Isentropic
A bar of copper and steel form a composite system, which is heated to a temperature of 40°C. The stress induced in the copper bar will be
Tensile
Compressive
Shear
Zero
An adiabatic process is one in which
No heat enters or leaves the gas
The temperature of the gas changes
The change in internal energy is equal to the mechanical workdone
All of the above
The absolute zero temperature is taken as
237°C
-273°C
-237°C
273°C
Workdone in a free expansion process is
Zero
Minimum
Maximum
Positive
The gas in cooling chamber of a closed cycle gas turbine is cooled at
Constant volume
Constant temperature
Constant pressure
None of these
First law of thermodynamics deals with
Conservation of heat
Conservation of momentum
Conservation of mass
Conservation of energy
The principal constituents of a fuel are
Carbon and hydrogen
Oxygen and hydrogen
Sulphur and oxygen
Sulphur and hydrogen
A series of operations, which takes place in a certain order and restore the initial conditions at the end, is known as
Reversible cycle
Irreversible cycle
Thermodynamic cycle
None of these
A process, in which the temperature of the working substance remains constant during its expansion or compression, is called
Isothermal process
Hyperbolic process
Adiabatic process
Polytropic process
Strain energy is the
Energy stored in a body when strained within elastic limits
Energy stored in a body when strained up to the breaking of a specimen
Maximum strain energy which can be stored in a body
Proof resilience per unit volume of a material
The deformation per unit length is called
Tensile stress
Compressive stress
Shear stress
Strain
During which of the following process does heat rejection takes place in Carnot cycle?
Isothermal expansion
Isentropic expansion
Isothermal compression
Isentropic compression
For riveting, the size of hole drilled in plates is __________ shank diameter of rivet.
Equal to
Less than
Greater than
None of these
Which of the following is a proper sequence?
Proportional limit, elastic limit, yielding, failure
Elastic limit, proportional limit, yielding, failure
Yielding, proportional limit, elastic limit, failure
None of the above
The heat absorbed or rejected by the working substance is given by (where ds = Increase or decrease of entropy, T = Absolute temperature, and dQ = Heat absorbed or rejected)
δQ = T.ds
δQ = T/ds
dQ = ds/T
None of these
A boiler shell 200 cm diameter and plate thickness 1.5 cm is subjected to internal pressure of 1.5 MN/m, and then the hoop stress will be
30 MN/m²
50 MN/m²
100 MN/m²
200 MN/m²
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
Cracking
Carbonisation
Fractional distillation
Full distillation
The general gas energy equation is (where Q1 - 2 = Heat supplied, dU = Change in internal energy, and W1 - 2 = Work done in heat units)
Q1 - 2 = dU + W1 - 2
Q1 - 2 = dU - W1 - 2
Q1 - 2 = dU/W1 - 2
Q1 - 2 = dU × W1 - 2