Which of the following cycles has maximum efficiency?
Rankine
Stirling
Carnot
Brayton
Correct Answer :
C. Carnot
Related Questions
The natural solid fuel is
Wood
Coke
Anthracite coal
Pulverised coal
For the same compression ratio, the efficiency of dual combustion cycle is
Greater than Diesel cycle and less than Otto cycle
Less than Diesel cycle and greater than Otto cycle
Greater than Diesel cycle
Less than Diesel cycle
The efficiency of Diesel cycle with decrease in cut-off
Increases
Decreases
First increases and then decreases
First decreases and then increases
In a prismatic member made of two materials so joined that they deform equally under axial stress, the unit stresses in two materials are
Equal
Proportional to their respective moduli of elasticity
Inversely proportional to their moduli of elasticity
Average of the sum of moduli of elasticity
When a body is subjected to a direct tensile stress (σx) in one plane accompanied by a simple shear stress (τxy), the maximum normal stress i
(σx/2) + (1/2) × √(σx² + 4 τ²xy)
(σx/2) - (1/2) × √(σx² + 4 τ²xy)
(σx/2) + (1/2) × √(σx² - 4 τ²xy)
(1/2) × √(σx² + 4 τ²xy)
High air-fuel ratio in gas turbines
Increases power output
Improves thermal efficiency
Reduces exhaust temperature
Do not damage turbine blades
Percentage reduction of area in performing tensile test on cast iron may be of the order of
50 %
25 %
0 %
15 %
The neutral axis of a transverse section of a beam passes through the centre of gravity of the section and is
In the vertical plane
In the horizontal plane
In the same plane in which the beam bends
At right angle to the plane in which the beam bends
The radius of the Mohrs circle in the given figure is equal to
Sum of two principal stresses
Difference of two principal stresses
Half the sum of two principal stresses
Half the difference of two principal stresses
If the rivets in adjacent rows are staggered and the outermost row has only one rivets, the arrangement of the rivets is called
Chain riveting
Zigzag riveting
Diamond riveting
Crisscross riveting
The value of Poisson's ratio for steel is between
0.01 to 0.1
0.23 to 0.27
0.25 to 0.33
0.4 to 0.6
The thermal efficiency of an ideal gas turbine plant is given by (where r = Pressure ratio)
rγ - 1
1 - rγ - 1
1 - (1/r) γ/γ - 1
1 - (1/r) γ - 1/ γ
The sum of internal energy (U) and the product of pressure and volume (p.v) is known as
Workdone
Entropy
Enthalpy
None of these
An isothermal process is governed by
Boyle's law
Charles' law
Gay-Lussac law
Avogadro's law
The assumption made in Euler's column theory is that
The failure of column occurs due to buckling alone
The length of column is very large as compared to its cross-sectional dimensions
The column material obeys Hooke's law
All of the above
A fletched beam is used to
Change the shape of the beam
Effect the saving in material
Equalise the strength in tension and compression
Increase the cross-section of the beam
One reversible heat engine operates between 1600 K and T2 K and another reversible heat engine operates between T2 K and 400 K. If both the engines have the same heat input and output, then temperature T2 is equal to
800 K
1000 K
1200 K
1400 K
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
The maximum diameter of the hole that can be punched from a plate of maximum shear stress 1/4th of its maximum crushing stress of punch, is equal to (where t = Thickness of the plate)
t
2t
4t
8t
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
Which of the following statement is correct?
The stress is the pressure per unit area
The strain is expressed in mm
Hook's law holds good upto the breaking point
Stress is directly proportional to strain within elastic limit
The columns whose slenderness ratio is less than 80, are known as
Short columns
Long columns
Weak columns
Medium columns
The efficiency of Diesel cycle increases with
Decrease in cut-off
Increase in cut-off
Constant cut-off
None of these
The heat supplied to the gas at constant volume is (where m = Mass of gas, cv = Specific heat at constant volume, cp = Specific heat at constant pressure, T2 - T1 = Rise in temperature, and R = Gas constant)
mR (T2 - T1)
mcv (T2 - T1)
mcp (T2 - T1)
mcp (T2 + T1)
The atomic mass of sulphur is
12
14
16
32
Young's modulus is defined as the ratio of
Volumetric stress and volumetric strain
Lateral stress and lateral strain
Longitudinal stress and longitudinal strain
Shear stress to shear strain
Youngs modulus of a wire is defined as the stress which will increase the length of wire compared to its original length by
Half
Same amount
Double
One-fourth
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.
Kerosene is distilled at
65° to 220°C
220° to 345°C
345° to 470°C
470° to 550°C
Which of the following cycles has maximum efficiency?
Rankine
Stirling
Carnot
Brayton