Brass parts with high residual tensile stress at the surface are susceptible to season cracking (i.e. spontaneous cracking occuring on exposure to atmospheric corrosion), if its zinc percentage is more than
Select an option to see the answer and solution.
With increase in impurities in metals, their corrosion resistances
A. Increase
B. Decrease
C. Remain same
D. May increase or decrease ; depending on the type of metal
Select an option to see the answer and solution.
Uniform ramming of sand in green sand moulding process leads to
A. Reduced chance of gas porosity
B. Greater dimensional stability of the casting
C. Uniform flow of molten metal into the mould cavity
D. Less sand expansion type of casting defect
Select an option to see the answer and solution.
Pick out the wrong statement. Termination of polymerisation reaction occurs, if the
A. Catalyst supply is stopped
B. Monomer supply is exhausted
C. Impurities present in monomers interfere with the chemical reaction
D. Two ends of a chain of molecules join
Select an option to see the answer and solution.
Statistical quality control was developed by __________ , an American scientist during world war II.
A. Water shewhart
B. Fredric Taylor
C. John Wright
D. Woolmer
Select an option to see the answer and solution.
Most important property of steels for use in automobile bodies is the
A. Formability
B. Yield strength
C. Toughness
D. Resilience
Select an option to see the answer and solution.
The function of neutral flux used in the pyrometallurgy of metal extraction is to increase the __________ of the slag.
A. Fluidity
B. Basicity
C. Acidity
D. Viscosity
Select an option to see the answer and solution.
In a titration involving weak acid and strong base, the preferred indicator is
A. Methyl orange
B. Phenolphthalein
C. Ethyl orange
D. Fehling's solution
Select an option to see the answer and solution.
Projection welding & stud welding is categorised as the __________ welding.
A. Pressure
B. Thermit
C. Resistance
D. Arc
Select an option to see the answer and solution.
Filler metal is not used in the __________ welding.
A. Seam
B. Electric spot
C. Projection
D. All of the above
Select an option to see the answer and solution.
Consumable electrodes are used in the __________ welding.
A. Gas
B. Arc
C. Thermit
D. Resistance
Select an option to see the answer and solution.
Nusselt number/Biot number varies
A. Inversely with thermal conductivity
B. Directly with heat transfer co-efficient
C. Directly with thermal conductivity
D. Inversely with the dimension of the solid
Select an option to see the answer and solution.
The same volume of all gases is representative of their
A. Specific gravities
B. Densities
C. Gas characteristic constants
D. Molecular weights
Select an option to see the answer and solution.
The most important function of a washer is to provide bearing area and washers are normally specified by their hole diameters. The diameter of washer as compared to the nut is
A. More
B. Less
C. Same
D. More but less than the diameter of bolt
Select an option to see the answer and solution.
Silicon in steel
A. Makes it usable in almost all magnetic circuits where alternating current is used
B. Increases its electrical resistivity and decreases the hysteresis loss
C. Is present upto 5% & 4% respectively when used in transformers & motor armatures
D. All of the above
Select an option to see the answer and solution.
Carbon supply in pack carburising process is in the form of
A. Charcoal
B. Calcium carbide
C. Hydrocarbon oil
D. Graphite
Select an option to see the answer and solution.
The two elements required to form substitutional solid solution should not have
A. Same crystalline structure
B. Same valancy
C. Widely differing electronegativity
D. Same atomic sizes
Select an option to see the answer and solution.
Solution loss reaction occurs
A. In the blast furnace shaft
B. During pretreatment of hot metal
C. In the L.D. process
D. During deoxidation in the ladle
Select an option to see the answer and solution.
The bulk modulus of a material with Poisson's ratio of 0.5 is equal to
A. 3 × Young's modulus
B. Young's modulus
C. Infinity
D. Zero
Select an option to see the answer and solution.
Air-petrol ratio for maximum power generation in spark ignition engine is about
A. 6:1
B. 12 : 1
C. 18 : 1
D. 24 : 1
Select an option to see the answer and solution.
