Function of fusible plug in a boiler is to
Drain out water and sludge from the boiler during repair
Put off fire in the furnace when water level in the boiler falls to unsafe limit
Guard the boiler in case of abnormal rise in steam pressure
All (A), (B) & (C)
Correct Answer :
B. Put off fire in the furnace when water level in the boiler falls to unsafe limit
Related Questions
Earing is a defect found in steels after the following metal working operation.
Extrusion
Rolling
Deep drawing
Wire drawing
Oxygen cylinders used for autogenous (cutting/welding) purposes are
Seamless & made of steel
Heat treated before use
Made by sand casting
Welded steel cylinders
'Ice point' is designated on Fahrenheit temperature scale by
0°
32°
62°
212°
During sensible cooling of air, its wet bulb temperature
Decreases but dew point remains constant
Increases but dew point remains constant
Increases & the dew point decreases
Decreases & the dew point increases
In an eutectic system, two elements are completely
Soluble in solid state
Insoluble in liquid state
Insoluble in both solid & liquid state
Soluble in liquid state
Air/fuel ratio by weight for combustion of methane with theoretical quantity of air will be about
9 : 1
17 : 1
23 : 1
29 : 1
According to thermodynamic Fahrenheit scale, the fundamental interval between ice point to steam point is
180°
212°
32°
273°
Which of the following terminology is used for the temperature at which new grains are formed in a metal?
Eutectic temperature
Lower critical temperature
Recrystallisation temperature
Upper critical temperature
Batch process is preferred over continuous process, when the
Product yields and quality cannot be achieved in continuous process, because of long residence time
Sales demand of product is not steady
Same equipment cannot be used for several processes of the same nature
All (A), (B) & (C)
Consider the equilibrium A(g) + B(g) = AB(g). When the partial pressure of A is 10-2 atm, the partial pressure of B is 10-3 atm and the partial pressure of AB is 1 atm, the equilibrium constant 'K' is
10 atm-1
105 atm-1
10 (dimensionless)
105 (dimensionless)
__________ of test specimens is not involved in any hardness testing method.
Fracture
Indentation
Wear
Scratch
The most prominent single cause of corrosion in boiler-tubes, drums, economisers and steam superheaters in a thermal power plant boiler is the
Water alkalinity & leakage
Hydrazine addition during feed water treatment
Release of non-condensable gas from water in the boiler
Scale formation
If a nuclear reactor produces more fissile nuclear fuel than it consumes, then it is called a __________ reactor.
Critical
Breeder
Fertile
Heterogeneous
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
Lead is poured into the joint between two __________ pipes.
Mild steel
Concrete
Cast iron
Asbestos cement
Case hardening of a material is
Followed by tempering or carburising
Preceded by its tempering
Done to get a soft ductile interior with a very hard surface
Carried out to get extreme hardness in its core
Pick out the wrong statement.
Weldability of high carbon steel is poorer compared to low carbon steel
Invar is a magnetic alloy
Magnetic permeability of the diamagnetic material is less than one
Martenistic transformation never goes to completion (i.e., 100%) at room temperature
Maximum change in the hardness of martensite occurs in the carbon content range of __________ percent in steel.
0.01 to 0.10
0.2 to 0.4
0.5 to 0.7
0.8 to 1.0
Materials having __________ lattice structure are usually the most ductile.
Body centred cubic (bcc)
Hexagonal close packed (hcp)
Face centred cubic (fcc)
None of these
The surface tension of a liquid, at critical temperature is
Indeterminate
Zero
Infinity
Same as that at any other temperature
When an isolated thermodynamic system executes a process,
Work is done
Heat transfer takes place
Mass flow occurs across the boundary of the system
No chemical reaction takes place within the system
The unit of gc is
lbm/lbf. ft/sec2
lbf/lbm. ft/sec2
ft/sec2
lbm/lbf. sec2/ft
Nusselt number/Biot number varies
Inversely with thermal conductivity
Directly with heat transfer co-efficient
Directly with thermal conductivity
Inversely with the dimension of the solid
Pressure required to increase the density of water by about 1% is __________ atmosphere.
10
50
200
1000
Powder metallurgy technique is used in the production of __________ tools.
Tungsten carbide
High carbon steel
High speed steel
Drilling
Unit of surface tension in S.I. unit is
Watt/m
Joule/
Newton/
Joule/m
As the fluid flow rate increases, the float of the Rotameter
Rises in the tube
Rotates at higher speed
Rotates at lower speed
Drops down in the tube
The most suitable material for die casting is
Iron
Copper
Steel
Nickel
Cold working of a material results in increase in hardness, which is termed as the __________ hardening.
Cold
Work
Age
Induction
A material subjected __________ must have high resilience.
Shock loading
Vibration
Fatigue
Tension