When a bar is subjected to a change of temperature and its deformation is prevented, the stress induced in the bar is
Tensile stress
Compressive stress
Shear stress
Thermal stress
Correct Answer :
D. Thermal stress
Related Questions
The value of one bar (in S. I. units) is equal to
1 × 102 N/m2
1 × 103 N/m2
1 × 104 N/m2
1 × 105 N/m2
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
The property of a material by virtue of which a body returns to its original, shape after removal of the load is called
Plasticity
Elasticity
Ductility
Malleability
The efficiency of Diesel cycle depends upon
Temperature limits
Pressure ratio
Compression ratio
Cut-off ratio and compression ratio
When a gas is heated at constant volume
Its temperature will increase
Its pressure will increase
Both temperature and pressure will increase
Neither temperature nor pressure will increase
The hard coke is obtained when carbonisation of coal is carried out at
300° to 500°C
500° to 700°C
700° to 900°C
900° to 1100°C
The state of a substance whose evaporation from its liquid state is complete, is known as
Vapour
Perfect gas
Air
Steam
For the same maximum pressure and temperature,
Otto cycle is more efficient than Diesel cycle
Diesel cycle is more efficient than Otto cycle
Dual cycle is more efficient than Otto and Diesel cycles
Dual cycle is less efficient than Otto and Diesel cycles
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
When a gas is heated, change takes place in
Pressure
Volume
Temperature
All of these
Reversed joule cycle is called
Carnot cycle
Rankine cycle
Brayton cycle
Bell Coleman cycle
The layer at the centre of gravity of the beam as shown in the below figure, will be
In tension
In compression
Neither in tension nor in compression
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
A close cycle gas turbine gives __________ efficiency as compared to an open cycle gas turbine.
Same
Lower
Higher
None of these
Producer gas is obtained by
Partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast
Carbonisation of bituminous coal
Passing steam over incandescent coke
Passing air and a large amount of steam over waste coal at about 650°C
The heat energy stored in the gas and used for raising the temperature of the gas is known as
External energy
Internal energy
Kinetic energy
Molecular energy
The bending moment at a point on a beam is the algebraic ________ of all the moments on either side of the point.
Sum
Difference
Multiplication
None of the above
Which of the following process can be made reversible with the help of a regenerator?
Constant pressure process
Constant volume process
Constant pvn process
All of these
When a body is subjected to biaxial stress i.e. direct stresses (σx) and (σy) in two mutually perpendicular planes accompanied by a simple shear stress (τxy), then minimum normal stress is
(σx + σy)/2 + (1/2) × √[(σx - σy)² + 4 τ²xy]
(σx + σy)/2 - (1/2) × √[(σx - σy)² + 4 τ²xy]
(σx - σy)/2 + (1/2) × √[(σx + σy)² + 4 τ²xy]
(σx - σy)/2 - (1/2) × √[(σx + σy)² + 4 τ²xy]
According to Avogadro's law, the density of any two gases is __________ their molecular masses, if the gases are at the same temperature and pressure.
Equal to
Directly proportional to
Inversely proportional to
None of these
Which of the following statement is correct according to Clausis statement of second law of thermodynamics?
It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature.
It is impossible to transfer heat from a body at a lower temperature to a body at a higher temperature, without the aid of an external source.
It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature by using refrigeration cycle.
None of the above
Which of the following has the minimum atomic mass?
Oxygen
Sulphur
Nitrogen
Carbon
A definite area or a space where some thermodynamic process takes place is known as
Thermodynamic system
Thermodynamic cycle
Thermodynamic process
Thermodynamic law
Volumetric strain for a rectangular specimen of length l, breadth b and thickness t subjected to a pull of P is given by
e (1 - 2m)
e (1 - 2/m)
e (m - 2)
e (2/m - 1)
Otto cycle is also known as
Constant pressure cycle
Constant volume cycle
Constant temperature cycle
Constant temperature and pressure cycle
In a steady flow process, the ratio of
Heat transfer is constant
Work transfer is constant
Mass flow at inlet and outlet is same
All of these
When a thin cylindrical shell is subjected to an internal pressure, the volumetric strain is (where ε₁ = Hoop strain, and ε₂ = Longitudinal strain)
2ε₁ - ε₂
2ε₁ + ε₂
2ε₂ - ε₁
2ε₂ + ε₁
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.
The efficiency of a Carnot engine depends on
Working substance
Design of engine
Size of engine
Temperatures of source and sink
The general law of expansion or compression is pvn = C, The process is said to be hyperbolic, if n is equal to
0
1
γ
∝