Fibre glass is a composite material of
Glass fibre in a polymer matrix
Glass fibre in a metallic matrix
Polymer fibre in a glassy matrix
Both 'b' & 'c'
Correct Answer :
A. Glass fibre in a polymer matrix
Related Questions
A jig is used while __________ a hole.
Boring
Counter boring
Drilling
Enlarging
The malleability of a material is the property by virtue of which it can be rolled or hammered into thin sheets. Which of the following materials has the maximum malleability?
Lead
Copper
Aluminium
Wrought iron
Pick out the wrong statement about coating/electroplating of metals.
Phosphate coating is used as an excellent base for paints & enamels
Phosphate coating is less corrosion resistant than chromate coating
The base metal to be electroplated is normally made the cathode of the electrolytic cell and coating metal is made the anode
Calorising is the process of coating steel with chromium
High endurance limit of carburised machine parts is because of the fact that carburisation
Suppresses any stress concentration produced in the parts
Enhances the yield point of the material
Introduces a compressive layer on the surface
Produces a better surface finish
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
Which of the following is a boiler accessory
i.e., not a boiler mounting?
Blow off cock
Feed check valve
Feed water pump
Stop valve
Regeneration of molecular sieve requires it to be heated to a temperature of about __________ °C.
80-120
200-300
600-800
1000-1100
Addition of small amount of __________ to grey cast iron is done to produce nodular grey cast iron.
Manganese
Phosphorous
Magnesium
Chromium
Plastics as a material of construction suffer from the drawback of low
Machinability
Density
Strength
Plastic deformation
Electrochemical corrosion can occur, only if __________ is present in contact with metal.
Air
Oxygen
Liquid medium
Gaseous medium
Pick out the wrong statement about nucleate boiling.
Bubble generation is by expansion of entrapped gas/vapour at small cavities in the surface
Surface temperature is greater than the saturation temperature of the liquid
Heat transfer from the surface of the liquid is less than that in film boiling
The temperature is less than that of film boiling
Brittleness induced due to the presence of sulphur in steel can be reduced by adding
Manganese
Magnesium
Vanadium
Copper
Work required for compression of a gas contained in a cylinder is 7000 kJ. During compression, heat interaction of 3000 kJ causes the surroundings to be heated. Internal energy change of the gas during the compression is __________ kJ.
+4000
-4000
10000
-10000
Resistance of an electrical conductor is proportional to its (where, l = length and A = cross-sectional area of the conductor)
A
l
A2
Both 'a' & 'b'
With increase in temperature, the electrical conductivity of semiconductors
Increases
Decreases
Remain constant
Either (A) or (B), depends on the type of semi-conductor
As per international norms, the maximum permissible value of noise level in the industrial environment is __________ decibels as measured at a distance of 1.5 metres from the source of noise.
110
85
60
45
'GASOHOL' widely used in Brazil as a motor fuel is a mixture of alcohol and
Petrol
LPG
Light hydrocarbon gases (e.g. butane or propane)
None of these
The highest stress that a material can withstand for a specified length of time without excessive deformation is called the __________ strength.
Creep
Endurance
Fatigue
None of these
The product of a commercial direct reduction process is
Liquid iron
Solid iron
Sponge iron
Iron saturated with carbon
Pick out the wrong statement.
The equivalent stiffness of two springs (of equal stiffness 'S') in series is S/2 while in parallel is 2S
For a helical spring, deflection is proportional to D3 (D = mean coil diameter) or d4 (d = wire diameter)
Crushing load or columns is less than the buckling load
Modulus of resilience is proportional to (stress at elastic limit)2
Natural water contains approximately __________ percent of heavy water.
0.015
0.71
1.2
3.5
Air standard Otto cycle is more efficient than the diesel cycle for the same
Heat addition & compression ratio
Heat addition & pressure
Compression ratio & pressure
Cylinder dimension & rpm
Hooke's law
Applies to elastic deformation
Applies beyond limit of proportionality in stress-strain curve
States that stress is inversely proportional to strain upto elastic limit
None of these
Fire refining process is employed in case of
Tin
Copper
Zinc
Aluminium
The passage between the nozzle and the __________ is called 'sprue' in case of injection moulding.
Runner
Cylinder
Mold
None of these
The normal stress is the same in all directions at a point in a fluid, only when the fluid
Is at rest & has zero viscosity
Is frictionless
Fluid layer has no motion relative to an adjacent layer of fluid
is incompressible & frictionless
Exposure to __________ accelerates the degradation of plastics.
Ultraviolet radiation
High atmospheric temperature
High ambient temperature
Damp atmosphere
Steel is welded using the __________ flame.
Carburising
Neutral
Oxidising
All (A), (B) & (C)
__________ is the trade name assigned to a nonferrous cast alloy composed of cobalt, chromium & tungsten.
Stellite
High speed steel
Cermet
Alnico
In the acid Bessemer process, the hot metal should have the following composition.
S < 0.05% and P < 0.05%
S < 0.05% and P < 1.5%
S < 0.05% and P > 1.5%
S > 1.5% and P < 0.05%