The percentage reduction in area of a cast iron specimen during tensile test would be of the order of
More than 50 %
25-50 %
10-25 %
Negligible
Correct Answer :
D. Negligible
Related Questions
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
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
The mass of carbon per kg of flue gas is given by
(11/3) CO2 + (3/7) CO
(3/7) CO2 + (11/3) CO
(7/3) CO2 + (3/11) CO
(3/11) CO2 + (7/3) CO
A cycle consisting of two adiabatic and two constant pressure processes is known as
Otto cycle
Ericsson cycle
Joule cycle
Stirling cycle
Which of the following is a reversible non-flow process?
Isochoric process
Isobaric process
Hyperbolic process
All of these
An isothermal process is governed by
Boyle's law
Charles' law
Gay-Lussac law
Avogadro's law
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
The efficiency of Stirling cycle is __________ Carnot cycle.
Greater than
Less than
Equal to
None of these
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 relation between Young's modulus (E), shear modulus (C) and bulk modulus (K) is given by
E = 3K.C/(3K + C)
E = 6K.C/(3K + C)
E = 9K.C/(3K + C)
E = 12K.C/(3K + C)
Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle
Combustion is at constant volume
Expansion and compression are isentropic
Maximum temperature is higher
Heat rejection is lower
The stress induced in a body due to suddenly applied load compared to when it is applied gradually is
Same
Half
Two times
Four times
The materials having same elastic properties in all directions are called
Ideal materials
Uniform materials
Isotropic materials
Piratical materials
Which of the following statement is correct?
The heat and work are boundary phenomena
The heat and work represent the energy crossing the boundary of the system
The heat and work are path functions
All of the above
The shear force at the centre of a simply supported beam with a gradually varying load from zero at both ends to w per metre at the centre, is
Zero
wl/4
wl/2
wl²/2
The pull required to crush the rivet per pitch length is
p.t.σt
d.t.σc
π/4 × d² × σt
π/4 × d² × σc
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 fuel mostly used in steam boilers is
Brown coal
Peat
Coking bituminous coal
Non-coking bituminous coal
Which of the following has the minimum atomic mass?
Oxygen
Sulphur
Nitrogen
Carbon
The amount of heat generated per kg of fuel is known as
Calorific value
Heat energy
Lower calorific value
Higher calorific value
The atomic mass of nitrogen is __________ oxygen.
Equal to
Less than
More than
None of these
The efficiency of Diesel cycle with decrease in cut-off
Increases
Decreases
First increases and then decreases
First decreases and then increases
The columns whose slenderness ratio is less than 80, are known as
Short columns
Long columns
Weak columns
Medium columns
Which of the following statement is incorrect?
The liquid fuels have higher calorific value than solid fuels
The solid fuels have higher calorific value than liquid fuels
A good fuel should have low ignition point
The liquid fuels consist of hydrocarbons
In closed cycle gas turbine, the air is compressed
Isothermally
Isentropically
Polytropically
None of these
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
The work ratio of simple gas turbine cycle depends upon
Maximum cycle temperature
Minimum cycle temperature
Pressure ratio
All of these
The efficiency of the Carnot cycle is (where T1 and T2 = Highest and lowest temperature during the cycle)
(T1/T2) - 1
1 - (T1/T2)
1 - (T2/T1)
1 + (T2/T1)
The torque transmitted by a solid shaft of diameter (D) is (where τ = Maximum allowable shear stress)
π /4 × τ × D³
π /16 × τ × D³
π /32 × τ × D³
π /64 × τ × D³
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