Tensile strength of a material is obtained by dividing the maximum load during the test by the
Area at the time of fracture
Original cross-sectional area
Average of (A) and (B)
Minimum area after fracture
Correct Answer :
B. Original cross-sectional area
Related Questions
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
Reversed joule cycle is called
Carnot cycle
Rankine cycle
Brayton cycle
Bell Coleman cycle
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
When wood is heated with a limited supply of air to a temperature not less than 280°C, the resulting fuel is
Coke
Wood charcoal
Bituminous coal
Briquetted coal
Select the correct statement as per Charles' law
p.v = constant, if T is kept constant
v/T = constant, if p is kept constant
p/T = constant, if v is kept constant
T/p = constant, if v is kept constant
The heat and mechanical energies are mutually convertible. This statement was established by
Boyle
Charles
Joule
None 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)
Kelvin-Planck's law deals with
Conservation of work
Conservation of heat
Conversion of heat into work
Conversion of work into heat
The materials having same elastic properties in all directions are called
Ideal materials
Uniform materials
Isotropic materials
Piratical materials
Which of the following is the correct statement?
For a given compression ratio, both Otto and Diesel cycles have the same efficiency.
For a given compression ratio, Otto cycle is more efficient than Diesel cycle.
For a given compression ratio, Diesel cycle is more efficient than Otto cycle.
The efficiency of Otto or Diesel cycle has nothing to do with compression ratio.
Workdone in a free expansion process is
Zero
Minimum
Maximum
Positive
If both Stirling and Carnot cycles operate within the same temperature limits, then efficiency of Stirling cycle as compared to Carnot cycle
More
Less
Equal
Depends on other factors
Which of the following has the minimum atomic mass?
Oxygen
Sulphur
Nitrogen
Carbon
One kilowatt is equal to
1 N-m/s
100 N-m
1000 N-m/s
1 × 106 N-m/s
According to Avogadro's law
The product of the gas constant and the molecular mass of an ideal gas is constant
The sum of partial pressure of the mixture of two gases is sum of the two
Equal volumes of all gases, at the same temperature and pressure, contain equal number of molecules
All of the above
When a system changes its state from one equilibrium state to another equilibrium state, then the path of successive states through which the system has passed, is known as
Thermodynamic law
Thermodynamic process
Thermodynamic cycle
None of these
Steam coal is a
Pulverised coal
Brown coal
Coking bituminous coal
Non-coking bituminous coal
The thermal efficiency of an ideal gas turbine plant is given by (where r = Pressure ratio)
rγ - 1
1 - rγ - 1
1 - (1/r) γ/γ - 1
1 - (1/r) γ - 1/ γ
Coke is produced
When coal is first dried and then crushed to a fine powder by pulverising machine
From the finely ground coal by moulding under pressure with or without a binding material
When coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel
By heating wood with a limited supply of air to a temperature not less than 280°C
Which of the following is a reversible non-flow process?
Isochoric process
Isobaric process
Hyperbolic process
All of these
The stress developed in a material at breaking point in extension is called
Breaking stress
Fracture stress
Yield point stress
Ultimate tensile stress
In a reversible adiabatic process, the ratio of T1/T2 is equal to
(p2/p1)γ - 1/ γ
(p1/p2)γ - 1/ γ
(v2/v1)γ - 1/ γ
(v1/v2)γ - 1/ γ
The gas constant (R) is equal to the __________ of two specific heats.
Sum
Difference
Product
Ratio
The gas turbine cycle with regenerator improves
Thermal efficiency
Work ratio
Avoids pollution
None of these
The work ratio of a gas turbine plant is given by
(Net work output)/(Workdone by the turbine)
(Net work output)/(Heat supplied)
(Actual temperature drop)/(Isentropic temperature drop)
(Isentropic increase in temperature)/(Actual increase in temperature)
The heating of a gas at constant pressure is governed by
Boyle's law
Charles' law
Gay-Lussac law
Avogadro's law
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 it is indicated that a member is elastic, it means that when force is applied, it will
Not deform
Be safest
Stretch
Not stretch
When a closely-coiled helical spring of mean diameter (D) is subjected to an axial load (W), the stiffness of the spring is given by
Cd⁴/D3n
Cd⁴/2D3n
Cd⁴/4D3n
Cd⁴/8D3n
A closely-coiled helical spring is cut into two halves. The stiffness of the resulting spring will be
Same
Double
Half
One-fourth