Joule-Thomson co-efficient is the ratio of
Pressure change to temperature change occuring during adiabatic compression of a gas
Pressure change to temperature change occuring during adiabatic throttling of a gas
Temperature change to pressure change occuring during adiabatic compression of a gas
Temperature change to pressure change occuring during adiabatic throttling of a gas
Correct Answer :
D. Temperature change to pressure change occuring during adiabatic throttling of a gas
Related Questions
Matte smelting is used in the extraction of
Lead
Zinc
Aluminium
Copper
Brittleness induced due to the presence of sulphur in steel can be reduced by adding
Manganese
Magnesium
Vanadium
Copper
Photographic plates are coated with
Silver nitrate
Silver halide
Calcium silicate
Metallic silver
Projection welding & stud welding is categorised as the __________ welding.
Pressure
Thermit
Resistance
Arc
Metal shots used in shot blasting are made of
Stellite
Steel
Bronze
Lead
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
__________ is not used as the control rod material in a nuclear reactor.
Cobalt
Hafnium
Cadmium
Boron
Spherical shape of mercury droplets is due to its
High viscosity
Low surface tension
High density
High surface tension
Steels with high carbon equivalent have poor Weldability, because in these steels during welding
Carbon and other alloying elements get oxidised from the weld pool
Excessive ferrite forms in the heat affected zone leading to poor toughness of the weld
Martensite forms in the heat affected zone leading to poor toughness/ductility of the weld
Segregation of carbon and other element occurs in the weld pool leading to poor properties of the weld
The main charge in blast furnace is usually
Iron ore & coke
Iron ore, coke & air
Limestone, coke & iron ore
Limestone, sand & iron ore
Softening of hardened steel is done by its
Normalising
Tempering
Annealing
Carburising
__________ property of steel increases by addition of large amount of silicon in it.
Mechanical
Machining
Magnetic
Refractory
The elastic strain in copper is due to the
Motion of dislocations
Stretching of atomic bonds
Breakage of atomic bonds
None of the above
Coating provided on the electrodes used in the arc welding is not expected to
Add alloying elements
Prevent electrode from contamination
Stabilise the arc
Provide protective atmosphere to weld
In condensers used in thermal power plants, steam is normally used in shell side and cooling water on the tube side, because of the reason that
Compared to the mass flow rate of cooling water, the rate of condensation of steam is invariably smaller
Maintaining vacuum on tube side is more difficult than that on the shell side
Water velocity can be increased conveniently to increase the overall heat transfer co-efficient because of its lower specific volume compared to steam
Condenser can act as a storage unit for condensed steam
Which of the following relationships is correct for relating the three elastic constants of an isotropic elastic material (where, E = Young's modulus, G = Modulus of rigidity or shear modulus v = Poisson's ratio)?
E = 2G (1 + v)
E = G (1 + v)
E = G (1 + v)/2
E = 2G (1 + 2v)
Compressed dry air is used as the cutting fluid, while machining
Steel
Cast iron
Aluminium
None of these
__________ cannot increase the fatigue strength of a material.
Grain refining
Grain coarsening
Surface hardening
Shot peening
Which of the following if present in iron ore, enhances its value?
Alumina
Alkali oxide
Lime & Magnesia
None of these
Titanium is added to molten aluminium alloys before casting for the purpose of
Grain refinement
Increasing corrosion resistance
Reducing porosity
Improving fluidity
In Imperial Smelting Process for extraction of zinc, zinc vapour thus produced is quenched in the external condenser by the use of the following:
Jet of water at high pressure
Blast of air
Mixture of water and air
Rain of molten lead
Annealing of cast iron
Softens it to facilitate machining
Decreases the free carbon
Increases the strength
None of these
Which of the following materials has the maximum shrinkage allowance?
Brass
Cast iron
Lead
Aluminium alloy
Liquid nitrogen containers can be made from
Ferritic stainless steel
HSLA steel
Titanium
Austenitic stainless steel
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)
Lead is poured into the joint between two- __________ pipes.
Mild steel
Concrete
Cast iron
Asbestos cement
Metalloids
Are good conductor of heat & electricity
Act as electron donors with metals & as electron acceptor with non-metals
Are not necessarily solids at room temperature
Are compounds that exhibit both metallic & non-metallic properties to some extent and are exemplified by elements like germanium, silicon & boron
In practice, the compression ratio of compression-ignition (CI) engine ranges from
15 to 25
5 to 10
40 to 55
60 to 70
Hot dipping process is used for coating a low melting point metal (e.g. Pb, Sn, Zn) on iron, steel & copper having relatively higher melting points. Which of the following is not a hot dipping process?
Galvanising
Tinning
Sherardizing
None of these
Function of gear box is to
Reduce the speed
Obtain variable speed
Increase the speed
Produce high torque