Pick out the wrong statement.
Ductile fracture of a stressed material, which exhibits a large plastic deformation is commonly caused by the formation and coalescence of voids in the necked region
Brittle fracture is caused by the propagation of pre-existing cracks in the material and involves minimum plastic deformation
Fatigue fracture of a material is always brittle in nature and takes place due to the existence of line imperfections
Brittle materials are generally tested in tension
Correct Answer :
B. Brittle fracture is caused by the propagation of pre-existing cracks in the material and involves minimum plastic deformation
Related Questions
Which of the following is an ore dressing operation?
Classification
Smelting
Roasting
None of these
Shaft/rotor speed is most accurately measured by a
Frequency counter
Tachometer
Strobometer
Speedometer
Which of the following mainly decides the current to be employed is arc welding?
Electrode size
Plate thickness
Voltage across the arc
Welded portion length
The yield point phenomenon observed in annealed low carbon steel is due to the presence of the following element.
Silicon
Carbon
Phosphorous
Chromium
Gantt charts are used for streamlining the
Inventory control
Production schedule
Sales forecasting
Quality control
Galvanic corrosion cannot be prevented by
Cathodic protection
Anodic protection
Usage of largest possible anodic area
Any one of these
The most commonly used moderator in nuclear power plants is
Graphite
Light water
Heavy water
Beryllium
About __________ ton of coke is required in a cupola to produce one ton of casting.
0.03
0.3
0.8
1.5
The thermodynamic law, 
= constant, is not followed by the
Free expansion of an ideal gas
Adiabatic expansion of steam in turbine
Adiabatic compression of air
Ideal compression of air
Force between the molecules of the same substance is called __________ force.
Adhesive
Cohesive
Molecular
Vander Walls
Photographic plates are coated with
Silver nitrate
Silver halide
Calcium silicate
Metallic silver
Induced draft fans provided in large thermal power plant boilers have __________ blades.
Forward curved
Backward curved
Double curved
Radial or straight
The bolt is subjected to __________ when the nut is tightened by putting the washer beneath it.
Tension
Shear
Compression
Bending & tension
Work hardenable alloy steel used to make the bucket wheel excavators, blades of bulldozers and other earth moving equipments contain iron, carbon and
Manganese
Silicon
Nickel
Chromium
With increase in compression ratio, the volumetric efficiency of air compressor
Increases
Decreases
Remain same
May increase or decrease (depends on the suction pressure)
Which of the following is an undesirable property of slag produced during the Pyrometallurgical method of metal extraction from its ore?
High fusibility & fluidity
High thermal conductivity
Low density
High chemical activity
What is the value of entropy at 273°K?
0
1
∞
None of these
With increase in temperature, the electrical conductivity of a __________ decreases.
Semi-conductor
Metal or alloy
Dielectric
None of these
Sub zero treatment of steel is done to
Suppress martensite transformation
Enhance its working performance in sub zero atmosphere
Reduce the retained austenite in hardened steel
Induce temper brittleness after its hardening
Nickel and __________ are the alloying element added in steel to increase its toughness.
Molybdenum
Chromium
Vanadium
Silicon
Heating the Hypo-eutectoid steels to 30°C above the upper critical temperature line, soaking at that temperature and then cooling slowly to the room temperature to form a pearlite & ferrite structure is called
Tempering
Hardening
Annealing
Normalising
An approximately __________ process exemplifies the flow of a gas through a very long pipe of uniform cross-section.
Adiabatic
Isothermal
Isentropic
Isochoric
What is the range of tempering temperature (°C) for most of the materials?
75-100
200-300
350-450
500-600
Surface tension of a liquid
Is due to intermolecular forces of cohesion
Decreases with rise in temperature
Is responsible for the spherical shape of an isolated liquid drop
All (A), (B) & (C)
Liquid nitrogen containers can be made from
Ferritic stainless steel
HSLA steel
Titanium
Austenitic stainless steel
Hot & cold working of material causes its __________ deformation.
Visco-elastic
Isotropic
Elastic
Plastic
At the point of boundary layer separation in fluid flow, the
Shear stress is maximum
Velocity gradient is flat
Density variation is maximum
Shear stress is zero
Heat flow across a hollow sphere of inner radius 'r1' and outer radius 'r2' is directly proportional to
(r2 - r1)/r1. r2
r1. r2/(r2 - r1)
(r2 + r1)/r1. r2
r1. r2/(r2 + r1)
Addition of __________ to steel does not help in improving its machinability.
Sulphur
Silicon
Lead
Phosphorous
The dew point of moist air becomes __________ with decrease in its relative humidity.
Less than the wet bulb temperature
More than the wet bulb temperature
More than the dry bulb temperature
Equal to wet bulb temperature