Which of the following commonly used condenser tube materials has the lowest thermal conductivity?
Admiralty brass
Stainless steel
Aluminium brass
Titanium
Correct Answer :
B. Stainless steel
Related Questions
Heat release during phase change is observed in case of a/an
Boiler
Condenser
Evaporator
All (A), (B) & (C)
Thermodynamic cycle involved in the working of a thermal power plant is the __________ cycle.
Joule
Carnot
Rankine
Brayton
A material in which the atoms are arranged regularly in some directions but not in others, is termed as 'mesomorphous material'; an example of which is
Lead
Glass
Mica
Silver
Which of the following is an undesirable property of slag produced during the Pyrometallurgical method of metal extraction from its ore?
High fusibility & fluidity
High thermal conductivity
Low density
High chemical activity
The pressure drop per unit length for laminar flow of fluid through a long pipe is proportional to (where, A = cross-sectional area of the pipe & D = Diameter of the pipe)
A
D
1/A
1/A2
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
The critical pressure at which the latent heat of vaporisation of steam becomes zero is __________ Kg/cm2.
273.15
225.65
100.03
373.15
The rolling process cannot be used to produce
Plates
Rods
Tubes
Wires
Powder metallurgy process does not make metal powder by
Atomisation
Grinding/milling
Hammering
Electrolytic deposition
Water hammer is caused in steam carrying pipelines, because of
Partial condensation of steam
Vibration of the pipeline
High degree of superheat of steam
Its exposure to torrential rain
Powder metallurgy is used to produce
High precision components with complex cavities and sharp features
Components of large size
Porosity free components
Components of such alloys whose constituents do not form alloys readily
Unbreakable crockeries are made from __________ polymers.
Polystyrene
Melamine
Polystyrene
Polyurethane
The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2 (when, T1 > T2) is given by (T1 - T2)/T1. The co-efficient of performance (CO.P.) of a Carnot heat pump operating between T1 and T2 is given by
T1/(T1-T2)
T2/(T1-T2)
T1/T2
T2/T1
Which of the following is the most wear resistant grade of carbide used for the cutting tools?
Aluminium carbide
Tungsten carbide
Nickel carbide
Iron carbide
Calorific value of __________ are almost same.
Lignite & anthracite coal
Lignite & coal gas
Petrol & diesel
Coal gas & natural gas
Which of the following has the highest modulus of elasticity (about 7 × 106 kg/cm2)?
High speed steel
Stainless steel
Tungsten carbide
Superalloys
In a furnace with heating element temperature at 1700°C, the dominant mechanism of heat transfer will be
Conduction
Radiation
Natural convection
Forced convection
The size of the tetrahedral void in the closest packing of atoms is __________ that of the octahedral void.
Equal to
Greater than
Less than
Either (A), (B) or (C); depends on the size of atom
In chemical dehumidification of air
Both specific humidity & dry bulb temperature increases
Both specific humidity & dry bulb temperature decreases
Specific humidity decreases & dry bulb temperature increases
Specific humidity increases & dry bulb temperature decreases
A material being tested for endurance strength is subjected to the __________ load.
Impact
Completely reversed
Dynamic
Static & dynamic
Which of the following low melting alloy containing bismuth and lead is used for electric fuse?
Wood's metal
Babbitt metal
Monel metal
Duralumin
Material of construction of the electrode used in the electric resistance welding is
Stainless steel
Graphite
Copper
Steel
Wrought iron does not have
Uniform strength in all directions
Ability to hold protective coating
High ductility & corrosion resistance
Easily weldable characteristics
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)
Oxyacetylene reducing flame is used while carrying out welding on
Alloy steel
Grey cast iron
Mild steel
High carbon steel
Increase in the entropy of a system represents the
Degradation of energy
Decrease in system pressure
Increase in the availability of energy
Increase in the temperature
__________ stress cannot be sustained by a fluid in equilibrium.
Shear
Tensile
Compressive
None of these
Upto the critical radius of insulation, added insulation, will
Increase the heat loss
Decrease heat loss and will have no effect beyond that
Decrease heat flux
Reduce convection heat loss compared to conduction heat less
The leaching solvent used in Baeyer's process for the purification of bauxite is
Ammonium hydroxide
Sodium carbonate
Sodium hydroxide
Ammonium carbonate
Identify the correct statement with reference to the extractive metallurgy of aluminium.
The electrolyte consists of molten Na3AlF6 with approximately 1 to 8% Al2O3
Approximately 80% of the aluminium deposited on the cathode comes from cryolite
Sodium is deposited along with aluminium, but is immediately vaporised
Anode effect sets in when the cryolite concentration goes below 40%.