The softness or hardness of a grinding wheel depends upon the type & amount of bonding material used. For general purpose cutter grinding __________ grinding wheel is normally used.
Hard
Soft
Silicon carbide
Aluminium oxide
Correct Answer :
D. Aluminium oxide
Related Questions
Absolute zero pressure can be attained at a temperature of
0°C
50°K
0°R
None of these
Angular displacement can be measured suitably by a
Shaft encoder
Linear variable differential transducer (LVDT)
Stroboscope
Tachometer
Carbon is present in the form of __________ in grey cast iron.
Spheroids
Nodular aggregates of graphite
Flakes
Cementite
Which of the following varies as the square root of oil pressure during atomisation of fuel oil through a pressure jet burner?
Output & fineness
Velocity
Both (A) & (B)
None of these
For the Stoke's law to be valid in the case of a falling sphere in a fluid, the
Reynolds number (based on sphere diameter) should be < 1
Flow around the sphere should be in turbulent region
Sphere must be metallic
Fluid density should be constant
A polymer is termed as an 'elastomer', if its percentage elongation is more than 100%. An elastomer is termed as 'rubber' if its percentage elongation is more than __________ percent.
150
200
300
400
The ratio of thermal & electrical conductivity is same for all the metals at the same temperature; and at around room temperature, this ratio is proportional to(where, T = absolute temperature, °K)
T
1/T
T2
1/T2
A solar cell converts the sunlight directly into __________ energy.
Thermal
Electrical
Mechanical
Chemical
Secondary hardening in steels arises out of the
Precipitation of fine alloy carbides at high temperatures
Refinement of ferrite grain size by working
Decomposition of retained austenite upon heat treatment
Precipitation of complex inter-metallic upon heat treatment
Fire in fuel gas pipelines is extinguished most effectively by
Spraying water
Blanketting the area with nitrogen atmosphere
Fire fighting foam
None of these
Nusselt number is related to the Reynolds number (Re) in turbulent & laminar flow respectively as
Re0.5, Re0.8
Re0.8, Re-0.5
Re0.8, Re0.5
Re-0.8, Re0.5
Metallic surveying tapes are made of __________ which has a low co-efficient of expansion & enough strength.
Invar
Hastelloy
Duralumin
Monel metal
According to maximum shear stress failure criterion, yielding in material occurs, when the maximum shear stress is equal to __________ times the yield stress.
0.5
2
√2
√3/2
Cupola produces __________ iron.
Pig
Cast
Wrought
Carbon free
__________ is a special constituent of chlorophyll without which photosynthesis is not possible.
Calcium
Nitrogen
Phosphorous
Hydrogen
Minimum safe distance between two liquid fuel storage tanks is equal to (where, H = height of the tank)
H
H/2
H/4
H/6
Cold chisels hammers are made of
High speed steel
High carbon steel
Forged steel
Mild steel
Annealing of white cast iron produces __________ iron.
Grey
Nodular
Malleable
Spheroidal
Nitriding of a steel part does not increase its
Grain size
Fatigue limit
Surface hardness
Wear resistance
The yield point phenomenon observed in annealed low carbon steel is due to the presence of the following element.
Silicon
Carbon
Phosphorous
Chromium
Temperature of hot gases flowing in a pipe is measured by a thermocouple inserted in the thermal well. The thermal well made of __________ will facilitate the most accurate measurement of the temperature.
Copper
Steel
Aluminium
Brass
Maximum amount of thermal radiation is emitted at all wavelengths at any specified temperature by a/an __________ body.
Grey
Black
Opaque
White
Preheating before welding is done to
Make the plate softer
Burn oil & grease sticking to plate surfaces
Avoid plate distortion
Prevent cold cracks
Fibre reinforced plastic (FRP) are
Made of glass fibre and thermoplastic resins
Anisotropic
Made of thermosetting resin and glass fibre
Both 'b' & 'c'
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)
Heat transfer to the water wall in a high pressure water wall type boiler furnace is mainly by
Conduction
Convection
Radiation
Both 'a' & 'b'
Solidification time of a molten metal in a casting is proportional to (where, V = volume of metal & A = its surface area; in the casting)
V/A
V/A2
V2/A
V2/A2
Half life of a radioactive isotope corresponds to the time required for half of the __________ to decay.
Atoms
Neutrons
Nucleons
Electrons
Wrought iron does not have
Uniform strength in all directions
Ability to hold protective coating
High ductility & corrosion resistance
Easily weldable characteristics
Holes for riveting purposes should be preferably made by
Cutting torch
Drilling
Punching
None of these