Fire in fuel gas pipelines is extinguished most effectively by
Spraying water
Blanketting the area with nitrogen atmosphere
Fire fighting foam
None of these
Correct Answer :
B. Blanketting the area with nitrogen atmosphere
Related Questions
The most important consideration in value engineering is the
Profit maximisation
Customer satisfaction
Cost reduction
Process improvement
Which of the following materials does not form adherent oxide film on surface?
Copper
Nickel
Aluminium
Gold & silver
Ferromagnetic materials owe their properties to __________ inner sub-shells.
Completely filled
Partially filled
Equally filled
Vacant
Copper deposits are found in India at the following location:
Kudremukh
Kolar
Khetri
Ramagundam
An abrupt and sudden fall in the reading of barometer is an indication of the
Storm
Rain
Clear weather
Cold wave
Which of the following is not a principal alloying element for the structural steel?
Molybdenum
Nickel
Manganese
Chromium
Silicon percentage in the silicon steel used for electrical appliances/equipments is
0.3-0.4
12-14
3-4
20-25
The maximum thickness of the metal which can be welded using ultrasonic welding is __________ mm.
0.5
3
10
25
In case of simple harmonic motion, displacement is proportional to the
Velocity
Acceleration
Both (A) & (B)
Neither (A) nor (B)
__________ cannot increase the fatigue strength of a material.
Grain refining
Grain coarsening
Surface hardening
Shot peening
Gratings is associated with the measurement of
Linear displacement
Concavity/convexity
Surface texture
Flatness
__________ test determines the yield strength, Young's modulus of elasticity, percentage reduction in area & percentage elongation of a material.
Tensile
Fatigue
Impact
None of these
__________ is the hardest oxide and is hence used where high wear resistance at high temperature is required.
Beryllium
Zirconia
Alumina
Magnesia
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
Heating the Hypo-eutectoid steels to 30°C above the upper critical temperature line, soaking at that temperature and then cooling slowly to the room temperature to form a pearlite & ferrite structure is called
Tempering
Hardening
Annealing
Normalising
The dimensional formula of bulk modulus of elasticity is same as that of the
Pressure
Density
Force
None of these
Isotropic materials have the same __________ in all directions.
Induced stresses
Density
Elastic properties
Thermal properties
Dew point temperature always gives an indication of the __________ of the moist air.
Dryness
Moisture content
Coolness
Latent heat
On being hit with a hammer, __________ will readily fracture.
Brass
Mild steel
Cast iron
Lead
Percentage of argon (by volume) in dry atmospheric air is about
0.09
0.3
0.57
0.94
Which of the following are made out of the carbon steel having carbon content of 0.9 to 1%?
Small punches, broaches reamers and springs
Cutlery, screws, rivets and files
Mandrels, twist drills, small lathe tools and razors
Forgings like can shaft, structural steel plate, threading dies and drawing dies
The thermodynamic law, 
= constant, is not followed by the
Free expansion of an ideal gas
Adiabatic expansion of steam in turbine
Adiabatic compression of air
Ideal compression of air
The capacity of a spring to store energy is called the spring form co-efficient. Stiffness of a spring is measured by the
Ability to absorb shock
Capacity to store energy
Ratio of the wire & coil diameters
Load to produce unit deflection
Diameter of the rivet to be provided on a 20 mm. thick boiler plate will be __________ mm.
10
20
30
40
Force between the molecules of the same substance is called __________ force.
Adhesive
Cohesive
Molecular
Vander Walls
__________ of grey cast iron produces white cast iron.
Tempering
Rapid heating
Rapid cooling
Slow cooling
One ton of refrigeration is not equivalent to the heat removal rate of
200 BTU/minute
50 kcal/minute
50 kJ/sec
3.5 KW
Gross national product (GNP) means the total value of __________ in a country.
Goods produced
Gold reserve
Earning of the citizens
Taxes paid
Which of the following is resistant to the action of both heat & chemicals?
Borosilicate glass
Silica glass
Soda lime glass
None of these
Cold cracking in the heat affected zone of a high strength steel weld can take place because of the
Retained austenite
Martensite formation
Relatively high sulphur content in the base metal
Sufficient hydrogen present in the welding arc