In a tensile test on mild steel specimen, the breaking stress as compared to ultimate tensile stress is
More
Less
Same
More/less depending on composition
Correct Answer :
B. Less
Related Questions
One Joule (J) is equal to
1 N-m
1 kN-m
10 N-m/s
10 kN-m/s
The root mean square velocity of the gas molecules is given by (where k = Boltzmann's constant, T = Absolute temperature, and m = Mass of one molecule of a gas)
√(KT/m)
√(2KT/m)
√(3KT/m)
√(5KT/m)
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
A hollow shaft of same cross-section area as compared to a solid shaft transmit
Same torque
Less torque
More torque
Unpredictable
The general gas energy equation is (where Q1 - 2 = Heat supplied, dU = Change in internal energy, and W1 - 2 = Work done in heat units)
Q1 - 2 = dU + W1 - 2
Q1 - 2 = dU - W1 - 2
Q1 - 2 = dU/W1 - 2
Q1 - 2 = dU × W1 - 2
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 moment of resistance of a balanced reinforced concrete beam is based on the stresses in
Steel only
Concrete only
Steel and concrete both
None of these
Elasticity of Mild Steel specimen is defined by
Hookes law
Yield point
Plastic flow
Proof stress
A shaft revolving at ω rad/s transmits torque (T) in Nm. The power developed is
T.ω watts
2π. T.ω watts
2π. T.ω/75 watts
2π. T.ω/4500 watts
Slenderness of a column is zero when
Ends are firmly fixed
Column is supported on all sides throughout the length
Length is equal to radius of gyration
Length is twice the radius of gyration
Otto cycle consists of following four processes
Two isothermals and two isentropic
Two isentropic and two constant volumes
Two isentropic, one constant volume and one constant pressure
Two isentropic and two constant pressures
For a simply supported beam of length l, when a concentrated load W is applied in the centre of the beam, the maximum deflection is
5WL³/ 384EI
WL³/384EI
WL³/ 348EI
WL³/ 48EI
Which of the following is a reversible non-flow process?
Isochoric process
Isobaric process
Hyperbolic process
All of these
The natural petroleum may be separated into
Petrol
Kerosene
Fuel oil
Lubricating oil
A column of length (l) with both ends fixed may be considered as equivalent to a column of length __________ with both ends hinged.
l/8
l/4
l/2
l
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
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
One kg of hydrogen requires 8 kg of oxygen and produces
1 kg of water
7 kg of water
8 kg of water
9 kg of water
Relation between cp and cv is given by (where cp = Specific heat at constant pressure, cv = Specific heat at constant volume, γ = cp/cv, known as adiabatic index, and R = Gas constant)
cv/ cp =R
cp - cv = R
cv = R/ γ-1
Both (B) and (C)
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)
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
If a material expands freely due to heating it will develop
Thermal stresses
Tensile stress
Bending
No stress
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 cycle in which heat is supplied at constant volume and rejected at constant pressure is known as
Dual combustion cycle
Diesel cycle
Atkinson cycle
Rankine cycle
The ultimate analysis of coal consists of the determination of the percentage of
Carbon
Hydrogen and nitrogen
Sulphur and ash
All of these
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
If percentage reduction in area of a certain specimen made of material 'A' under tensile test is 60% and the percentage reduction in area of a specimen with same dimensions made of material 'B' is 40%, then
The material A is more ductile than material B
The material B is more ductile than material A
The ductility of material A and B is equal
The material A is brittle and material B is ductile
The air standard efficiency of an Otto cycle is given by (where r = Compression ratio, and γ = Ratio of specific heats)
1 - rγ - 1
1 + rγ - 1
1 - (1/ rγ - 1)
1 + (1/ rγ - 1)
The volumetric or molar specific heat at constant pressure is the product of
Molecular mass of the gas and the specific heat at constant volume
Atomic mass of the gas and the gas constant
Molecular mass of the gas and the gas constant
None of the above
Which of the following statement is correct?
The increase in entropy is obtained from a given quantity of heat at a low temperature.
The change in entropy may be regarded as a measure of the rate of the availability or unavailability of heat for transformation into work.
The entropy represents the maximum amount of work obtainable per degree drop in temperature.
All of the above