A steel bar of 5 mm is heated from 25°C to 45°C and it is free to expand. The bar will induce
No stress
Shear stress
Tensile stress
Compressive stress
Correct Answer :
A. No stress
Related Questions
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
In a free expansion process,
W1 - 2 = 0
Q1 - 2 = 0
dU = 0
All of these
Within elastic limit, stress is
Inversely proportional to strain
Directly proportional to strain
Square root of strain
Equal to strain
Second law of thermodynamics defines
Heat
Work
Internal energy
Entropy
Stirling and Ericsson cycles are
Reversible cycles
Irreversible cycles
Semi-reversible cycles
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The efficiency of Diesel cycle depends upon
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Pressure ratio
Compression ratio
Cut-off ratio and compression ratio
When the gas is heated at constant volume, the heat supplied
Increases the internal energy of the gas and increases the temperature of the gas
Does some external work during expansion
Both (A) and (B)
None of these
The gas in cooling chamber of a closed cycle gas turbine is cooled at
Constant volume
Constant temperature
Constant pressure
None of these
Which of the following gas has the highest calorific value?
Coal gas
Producer gas
Mond gas
Blast furnace gas
A hollow shaft of same cross-section area as compared to a solid shaft transmit
Same torque
Less torque
More torque
Unpredictable
One molecule of oxygen is __________ times heavier than the hydrogen atom.
12
14
16
32
A key is subjected to side pressure as well at shearing forces. These pressures are called
Bearing stresses
Fatigue stresses
Crushing stresses
Resultant stresses
The heat and mechanical energies are mutually convertible. This statement was established by
Boyle
Charles
Joule
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
The ideal efficiency of a Brayton cycle with regeneration, with increase in pressure ratio will
Increase
Decrease
Remain unchanged
Increase/decrease depending on application
Workdone in a free expansion process is
Zero
Minimum
Maximum
Positive
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
The efficiency of Ericsson cycle is __________ Carnot cycle.
Greater than
Less than
Equal to
None of these
The mass of flue gas per kg of fuel is the ratio of the
Mass of oxygen in 1 kg of flue gas to the mass of oxygen in 1 kg of fuel
Mass of oxygen in 1 kg of fuel to the mass of oxygen in 1 kg of flue gas
Mass of carbon in 1 kg of flue gas to the mass of carbon in 1 kg of fuel
Mass of carbon in 1 kg of fuel to the mass of carbon in 1 kg of flue gas
An open cycle gas turbine works on
Carnot cycle
Otto cycle
Joule's cycle
Stirling cycle
Which is the incorrect statement about Carnot cycle?
It is used as the alternate standard of comparison of all heat engines.
All the heat engines are based on Carnot cycle.
It provides concept of maximising work output between the two temperature limits.
All of the above
The ratio of molar specific heats for mono-atomic gas is
1
1.4
1.67
1.87
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
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
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Oxygen
Sulphur
Nitrogen
Carbon
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Shear force changes sign
Shear force is maximum
Bending moment changes sign
Bending moment is maximum
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Carnot
Ericsson
Stirling
None of the above
The atomic mass of sulphur is
12
14
16
32
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Cd⁴/D3n
Cd⁴/2D3n
Cd⁴/4D3n
Cd⁴/8D3n
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Volume
Temperature
All of these