Material of construction of foundry crucible is
Lead
Stainless steel
Graphite
Cast iron
Correct Answer :
C. Graphite
Related Questions
Water hammer is caused in steam carrying pipelines, because of
Partial condensation of steam
Vibration of the pipeline
High degree of superheat of steam
Its exposure to torrential rain
In case of condensers & evaporators operating under given terminal conditions, LMTD (logarithmic mean temperature difference) for counter flow as compared to that for parallel flow is
More
Less
Equal
Much more
__________ rubber is generally used for making 'O' rings used for vacuum sealings.
Natural
Neoprene
Butadiene
Nitrile
When dry bulb temperature & wet bulb temperature of moist air is the same, it means that the
Partial pressure of water vapour is less than the total pressure
Humidity is < 100% & dew point temperature of air has not reached
Dew point temperature of air has not reached & air is not saturated fully
Air is fully saturated
In TIG welding, thoriated tungsten electrodes are used, because it
Has higher current carrying capacity
Has better electron emissivity
Is stronger than ordinary tungsten
Is easy to prepare
A dummy activity is used in PERT network to describe the
Precedence relationship
Resource idleness
Resource restriction
Necessary time delay
The wet bulb temperature is lower in dry air than in wet air at the same temperature. A dry bulb thermometer registers a higher temperature than a wet bulb thermometer except at __________ percent relative humidity.
0
100
50
None of these
The atmospheric temperature during melting of ice/snow (in the atmosphere)
Decreases
Increases
Remain same
May increase or decrease; depends on the altitude where snow melts
Angular displacement can be measured suitably by a
Shaft encoder
Linear variable differential transducer (LVDT)
Stroboscope
Tachometer
Nusselt number/Biot number varies
Inversely with thermal conductivity
Directly with heat transfer co-efficient
Directly with thermal conductivity
Inversely with the dimension of the solid
Specific gravity of hot metal (pig iron) is __________ times that of the blast furnace slag.
2
3
0.8
6
Annealing of cast iron
Softens it to facilitate machining
Decreases the free carbon
Increases the strength
None of these
An atom bomb works on the principle of
Nuclear fission
Nuclear fusion
Both the nuclear fission & fusion
Ionisation
Pick out the wrong statement.
A ferromagnetic material becomes paramagnetic above the 'Curie temperature'
Permanent magnets are made of hard materials, whereas electromagnets require soft magnetic materials
Soft magnetic materials (e.g., pure iron) have higher permeability and low hysterisis loss and coercive forces
Tungsten steel and alnico are not hard magnetic materials
Which of the following is preferred for riveting?
Lap joint
Butt joint
Either (A) or (B)
Neither (A) nor (B)
In the diving apparatus, helium is used along with oxygen, because it is
Easily available
Not soluble in blood at high pressure
Lighter than nitrogen
Completely miscible with oxygen
The boiling & freezing points on a newly defined temperature scale in degree 'D' are 400°D & 100°D respectively. The temperature reading corresponding to 60°C on this new temperature scale will be equal to __________ °D.
140
180
240
280
While the thermosetting polymers are amorphous in nature, the thermoplastic polymers are either amorphous or crystalline. The crystalline polymers are characterised by the
Low impact strength
High flexibility
Better finish and surface appearance
High plastic deformation
Theoretical volume of oxygen required for complete combustion of 1Nm3 of acetylene, in oxyacetylene welding is __________ Nm3.
0.5
1
1/3
2.5
Mild steel has __________ crystal lattice structure.
Face centred cubic (fcc)
Body centred cubic (bcc)
Orthorhombic
Cubic
In multipass welds, shot peening is done after each pass to
Close the surface porosity
Break the continuity of columnar grains
Flatten the weldment
Introduce texture in the weld
With increase in annealing temperature, the following defect density decreases.
Vacancy
Dislocation
Grain boundary
All of these
Spheroidising of a material is a/an __________ process.
Normalising
Annealing
Tempering
Hardening
During decarburising of a plain carbon steel, the thickness of ferrite layer growth is proportional to
Time
Square root of time
Square of time
Cube of time
Thermal diffusivity of a substance is proportional to (where, k = Thermal conductivity)
1/k
k
k2
1/k2
Wrought iron does not have
Uniform strength in all directions
Ability to hold protective coating
High ductility & corrosion resistance
Easily weldable characteristics
Pick out the wrong statement
Processing of thermosetting plastics is ideally done by injection moulding
Processing of thermoplastics is ideally done by compression moulding
Mass production of seamless pipes are done by electrical resistance welding (ERW)
Stretch forming is a process of cold drawing
Starting friction is low in case of the __________ lubrication.
Boundary
Hydrodynamic
Hydrostatic
Mixed/semi-fluid
Atomic __________ is a whole number for an element.
Number
Weight
Radius
None of these
Tip of the match stick contains a mixture of
K + S
K + S + K2Cr2O7
S + K2Cr2O7 + White P
None of these