The following thermocouple may be used for measuring temperature upto 1873°K.
Chromel-alumel
Copper-constantan
Platinum-platinum rhodium
Iron-constantan
Correct Answer :
C. Platinum-platinum rhodium
Related Questions
Preheating before welding is done to
Make the plate softer
Burn oil & grease sticking to plate surfaces
Avoid plate distortion
Prevent cold cracks
The dimensional formula of bulk modulus of elasticity is same as that of the
Pressure
Density
Force
None of these
Which of the following alloying elements is present in maximum percentage in high speed steel?
Molybdenum
Chromium
Tungsten
Vanadium
Normalising does not __________ of a metal.
Improve machinability & tensile strength
Remove internal stresses
Refine the structure
Remove strains caused by cold working
Globular form of cementite is formed during the __________ process.
Spheroidising
Hardening
Annealing
Normalising
Broaching tools are usually made of
Cermets
High speed steel
Tungsten carbide
Stellite
Superheating of steam is done at constant
Enthalpy
Entropy
Pressure
Volume
Coarse grained steels have
Low toughness
No tendency to distort
High density
Very high toughness
Metal cutting by oxy-acetylene flame is accomplished by the __________ of the metal.
Burning
Intensive oxidation
Evaporation
None of these
Consider an ideal solution of components A and B. The entropy of mixing per mole of an alloy containing 50% B is
R ln 2
-R ln 2
3 R ln 2
-3R ln 2
Which of the following materials does not form adherent oxide film on surface?
Copper
Nickel
Aluminium
Gold & silver
Which of the following is an ore dressing operation?
Classification
Smelting
Roasting
None of these
Pick out the correct statement.
Materials exhibiting high elasticity obey Hooke's law
The elastic behaviour of rubber under compression is the same as its behaviour under tension
The damping capacity of a material is due to its plastic deformation
The stress required to cause plastic flow in polycrystalline material is higher as compared to monocrystalline materials due to the presence of grains of different orientations
Thermit welding uses the following energy source.
Electrical energy
Chemical energy
Energy of high velocity electrons
Heat generated by friction
Chlorine acts as a bleaching agent only in the presence of
Dry air
Pure oxygen
Moisture
Sunlight
In case of water (Prandtl number ≈ 6) flowing over a flat plate heated over the entire length, the thermal boundary layer thickness as compared to hydrodynamic boundary layer thickness is
Less
More
Equal
Unpredictable
Pressure exerted by a liquid depends upon its
Surface tension
Density
Viscosity
Buoyancy
__________ of austenite decreases the hardenability in steel.
Fine grains
Coarse grains
Homogeneity
Dissolved elements (except cobalt)
Nickel is a __________ material.
Ferromagnetic
Semi-conductor
Paramagnetic
Ferroelectric
Transition from laminar flow to turbulent flow in fluid flow through a pipe does not depend upon the
Length of the pipe
Diameter of the pipe
Density of the fluid
Velocity of the fluid
Dowtherm is a
High temperature heating medium (a petroleum product)
Product of coal tar distillation
Very heat sensitive material
None of these
Desalination of water
Makes it potable
Makes it non-potable
Means distillation of water
None of these
Maximum permissible air velocity in pipelines is about __________ metre/second.
5
10
20
40
A jig is used while __________ a hole.
Boring
Counter boring
Drilling
Enlarging
Mild steel has __________ crystal lattice structure.
Face centred cubic (fcc)
Body centred cubic (bcc)
Orthorhombic
Cubic
Inertial forces are obtained, when the elastic forces are multiplied by __________ number.
Mach
Froude
Reynolds
Euler
Tumbling is the process of improving the __________ of the materials/parts.
Surface finish
Fatigue limit
Creep limit
Surface cleanliness
In __________ process, there is an increase in entropy with no degradation of energy.
Isothermal expansion
Isochoric heat addition
Polytropic expansion
Isobaric heat addition
Blow off cock is provided in steam boiler to
Guard the boiler in case of abnormal rise in steam pressure
Drain out water and sludge during its repair
Regulate the supply of water in boiler
Put out the fire in the furnace when the water level in the boiler falls to unsafe limit
Which of the following is an example of stress corrosion?
Season cracking of brass
Caustic embrittlement of steel
Both (A) & (B)
Neither (A) nor (B)