Percentage reduction in area performing tensile test on cast iron may be of the order of
50 %
25 %
20 %
30 %
Correct Answer :
C. 20 %
Related Questions
The strain energy stored in a solid circular shaft subjected to shear stress (τ), is: (Where G = Modulus of rigidity for the shaft material)
τ²/ 2G × Volume of shaft
τ/ 2G × Volume of shaft
τ²/ 4G × Volume of shaft
τ/ 4G × Volume of shaft
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
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
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 maximum 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]
The efficiency of Joule cycle is
Greater than Carnot cycle
Less than Carnot cycle
Equal to Carnot cycle
None of these
The maximum tangential stress in a thick cylindrical shell is always _________ the internal pressure acting on the shell.
Equal to
Less than
Greater than
None of these
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
The measurement of a thermodynamic property known as temperature is based on
Zeroth law of thermodynamics
First law of thermodynamics
Second law of thermodynamics
None of these
A mixture of gas expands from 0.03 m3 to 0.06 m3 at a constant pressure of 1 MPa and absorbs 84 kJ of heat during the process. The change in internal energy of the mixture is
30 kJ
54 kJ
84 kJ
114 kJ
The unit of energy is S. I. units is
Joule (J)
Joule metre (Jm)
Watt (W)
Joule/metre (J/m)
The following cycle is used for air craft refrigeration
Brayton cycle
Joule cycle
Carnot cycle
Reversed Brayton cycle
The efficiency and work ratio of a simple gas turbine cycle are
Very low
Low
High
Very high
The strain energy stored in a body due to suddenly applied load compared to when it is applied gradually is
Same
Twice
Four times
Eight times
The ratio of specific heat at constant pressure (cp) and specific heat at constant volume (cv) is
Equal to one
Less than one
Greater than one
None of these
The tensile strength of the welded joint for double fillet is (where s = Leg or size of the weld, l = Length of weld, and σt = Allowable tensile stress for weld metal)
0.5 s.l.σt
s.l.σt
√2 s.l.σt
2.s.l.σt
Diamond riveted joint can be adopted in the case of following type of joint
Butt joint
Lap joint
Double riveted lap joints
All types of joints
The behaviour of a perfect gas, undergoing any change in the variables which control physical properties, is governed by
Boyle's law
Charles' law
Gay-Lussac law
All of these
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 value of shear stress which is induced in the shaft due to the applied couple varies
From maximum at the centre to zero at the circumference
From zero at the centre to maximum at the circumference
From maximum at the centre to minimum at the circumference
From minimum at the centre to maximum at the circumference
The materials having same elastic properties in all directions are called
Ideal materials
Uniform materials
Isotropic materials
Piratical materials
The value of 1 mm of Hg is equal to
1.333 N/m2
13.33 N/m2
133.3 N/m2
1333 N/m2
A definite area or a space where some thermodynamic process takes place is known as
Thermodynamic system
Thermodynamic cycle
Thermodynamic process
Thermodynamic law
The safe twisting moment for a compound shaft is equal to the
Maximum calculated value
Minimum calculated value
Mean value
Extreme value
In a belt drive, the pulley diameter is doubled, the belt tension and pulley width remaining same. The changes required in key will be
Increase key length
Increase key depth
Increase key width
Double all the dimensions
The most probable velocity of the gas molecules is given by
√(KT/m)
√(2KT/m)
√(3KT/m)
√(5KT/m)
A cycle consisting of one constant pressure, one constant volume and two isentropic processes is known as
Carnot cycle
Stirling cycle
Otto cycle
Diesel cycle
Petrol is distilled at
65° to 220°C
220° to 345°C
345° to 470°C
470° to 550°C
The heat and mechanical energies are mutually convertible. This statement was established by
Boyle
Charles
Joule
None of these
One molecule of oxygen is __________ times heavier than the hydrogen atom.
12
14
16
32
The entropy may be expressed as a function of
Pressure and temperature
Temperature and volume
Heat and work
All of these