A composite bar made up of steel and copper bars of equal lengths are heated through 100°C. The stresses developed shall be
Tensile in both the material
Tensile in steel and compressive in copper
Compressive in steel and tensile in copper
Compressive in both the materials
Correct Answer :
D. Compressive in both the materials
Related Questions
The efficiency of the Carnot cycle may be increased by
Increasing the highest temperature
Decreasing the highest temperature
Increasing the lowest temperature
Keeping the lowest temperature constant
The heating of a gas at constant pressure is governed by
Boyle's law
Charles' law
Gay-Lussac law
Avogadro's law
The total energy of a molecule is shared equally by the various degrees of freedom possessed by it. This law is known as
Law of equipartition of energy
Law of conservation of energy
Law of degradation of energy
None of these
Elasticity of Mild Steel specimen is defined by
Hookes law
Yield point
Plastic flow
Proof stress
The ratio of lateral strain to the linear strain within elastic limit is known as
Young's modulus
Bulk modulus
Modulus of rigidity
Poisson's ratio
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
The efficiency of Carnot cycle depends upon
Temperature limits
Pressure ratio
Volume compression ratio
Cut-off ratio and compression ratio
The torsional rigidity of a shaft is expressed by the
Maximum torque it can transmit
Number of cycles it undergoes before failure
Elastic limit up to which it resists torsion, shear and bending stresses
Torque required to produce a twist of one radian per unit length of shaft
When the gas is heated at constant pressure, the heat supplied
Increases the internal energy of the gas
Increases the temperature of the gas
Does some external work during expansion
Both (B) and (C)
A coil is cut into two halves, the stiffness of cut coil will be
Double
Half
Same
None of these
The change of entropy, when heat is absorbed by the gas, is
Positive
Negative
Positive or negative
None of these
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
The extension of a circular bar tapering uniformly from diameter d₁ at one end to diameter d₂ at the other end and subjected to an axial pull of P is given by
δl = 4PE/ πl²
δl = 4πld²/PE
δl = 4Pl/πEd₁d₂
δl = 4PlE/ πd₁d₂
The calorific value of gaseous fuel is expressed in
kJ
kJ/kg
kJ/m2
kJ/m3
Carnot cycle has maximum efficiency for
Petrol engine
Diesel engine
Reversible engine
Irreversible engine
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
During which of the following process does heat rejection takes place in Carnot cycle?
Isothermal expansion
Isentropic expansion
Isothermal compression
Isentropic compression
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 value of gas constant (R) in S. I. units is
0.287 J/kgK
2.87 J/kgK
28.7 J/kgK
287 J/kgK
A simply supported beam with a gradually varying load from zero at B and w per unit length at A is shown in the below figure. The shear force at B is equal to
wl/6
wl/3
wl
2wl/3
The stress necessary to initiate yielding is
Considerably greater than that necessary to continue it
Considerably lesser than that necessary to continue it
Greater than that necessary to stop it
Lesser than that necessary to stop it
The amount of heat required to raise the temperature of 1 kg of water through one Kelvin is called
Specific heat at constant volume
Specific heat at constant pressure
kilo-Joule
None of these
The condition for the reversibility of a cycle is
The pressure and temperature of the working substance must not differ, appreciably, from those of the surroundings at any stage in the process
All the processes, taking place in the cycle of operation, must be extremely slow
The working parts of the engine must be friction free
All of the above
The given figure shows the Mohr's circle of stress for two unequal and like principal stresses (σx and σy) acting at a body across two mutually perpendicular planes. The normal stress on an oblique section making an angle θ with the minor principle plane is given by
OC
OP
OQ
PQ
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
The ideal efficiency of a Brayton cycle with regeneration, with increase in pressure ratio will
Increase
Decrease
Remain unchanged
Increase/decrease depending on application
A tri-atomic molecule consists of __________ atoms.
One
Two
Three
Four
The general law for the expansion or compression of gases, is
pv = C
pv = m R T
pvn = C
pvγ = C
Which of the following cycles is not a reversible cycle?
Carnot
Ericsson
Stirling
None of the above
In a uniform bar, supported at one end in position, the maximum stress under self weight of bar shall occur at the
Middle of bar
Supported end
Bottom end
None of these