The ratio of thermal & electrical conductivity is same for all the metals at the same temperature; and at around room temperature, this ratio is proportional to(where, T = absolute temperature, °K)
T
1/T
T2
1/T2
Correct Answer :
A. T
Related Questions
Addition of __________ to steel does not impart hardness.
Nickel
Copper
Chromium
Silicon
While the bin cards are used in the effective stores management, the queuing theory is associated with the __________ time.
Waiting
Idle
Inspection
Tool replacement
Dew point temperature always gives an indication of the __________ of the moist air.
Dryness
Moisture content
Coolness
Latent heat
Basicity 
of the slag in Indian blast furnace is in the range of
0.7-1.0
1.1-1.4
1.5 - 1.8
2.0 - 2.5
The following type of bonding is strongly directional in solids.
Vander Waal's
Ionic
Metallic
Covalent
Pick out the wrong statement.
A ferromagnetic material becomes paramagnetic above the 'Curie temperature'
Permanent magnets are made of hard materials, whereas electromagnets require soft magnetic materials
Soft magnetic materials (e.g., pure iron) have higher permeability and low hysterisis loss and coercive forces
Tungsten steel and alnico are not hard magnetic materials
__________ is not used as the control rod material in a nuclear reactor.
Cobalt
Hafnium
Cadmium
Boron
Carnot cycle is also termed as the constant __________ cycle in thermodynamics.
Entropy
Pressure
Volume
Heat
Which of the following materials has the maximum shrinkage allowance?
Brass
Cast iron
Lead
Aluminium alloy
Diffusion co-efficient of a metal in a solid solution depends upon its
Composition
Temperature
Both (A) & (B)
Neither (A) nor (B)
Heat release during phase change is observed in case of a/an
Boiler
Condenser
Evaporator
All (A), (B) & (C)
In TIG welding, thoriated tungsten electrodes are used, because it
Has higher current carrying capacity
Has better electron emissivity
Is stronger than ordinary tungsten
Is easy to prepare
A particle is settling in a liquid under Stokesian conditions. The free falling velocity of the particle is proportional to
√(Particle diameter)
Particle diameter
(Particle diameter)2
(Particle diameter)3
'Flare tower' used in industry is meant for
Venting off (after burning) the excess inflammable/toxic gases at high pressure
Absorbing the pollutant gases from the furnace exhaust
Cooling of furnace exhaust gases
None of these
Electrometallurgical methods of metal extraction is normally used for those metals
Whose oxide/ore is not reduced by carbon
Which fall in the category of alkali & alkaline earth metals
Which stands higher in the electrochemical series of the metal
All (A), (B) & (C)
Ceramic compounds as compared to metallic compounds
Crystallise faster
Resist greater tensile stress at room temperature
Have higher melting temperature
Are better conductor of electricity at higher temperature
__________ is used for tying the steel columns to concrete foundation.
Grouting
Eyebolt
Anchor bolts
Refractory castables
The heat treatment to which the steel wire containing > 0.25% carbon is subjected to is
Full annealing
Bright annealing
Patenting
None of these
Which of the following has the highest modulus of elasticity (about 7 × 106 kg/cm2)?
High speed steel
Stainless steel
Tungsten carbide
Superalloys
A reduction in thermal resistance during heat transfer does not occur in the
Convection heat transfer by stirring the fluid and cleaning the heating surface
Conduction heat transfer by reduction in the material thickness and increase in the thermal conductivity
Radiation heat transfer by increasing the temperature and reducing the emissivity
None of these
Which of the following is an unconventional source of energy?
Thermal power
Hydroelectric power
Nuclear-fusion power
Solar power
Probability of cavitation occuring becomes very high, when the local __________ resulting in water bubbles formation, which on rupture cause cavitation
Pressure falls below the vapour pressure
Pressure becomes very high
Temperature becomes low
All 'a', 'b' & 'c'
With increase in temperature, the electrical conductivity of a __________ decreases.
Semi-conductor
Metal or alloy
Dielectric
None of these
Which of the following is preferred for riveting?
Lap joint
Butt joint
Either (A) or (B)
Neither (A) nor (B)
A thin, flat & square plate measuring 2 m × 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will remain constant at 30°C, if the convective heat transfer co-efficient is __________ W/m2 °C.
50
100
150
200
The most serious manufacturing defect from fracture toughness point of view is
Surface roughness
Pores
Spherical inclusion
Crack
With increase in __________ Knocking tendency in a spark ignition petrol engine decreases.
Supercharging
Wall temperature
Compression ratio
Engine speed
Water-tube boiler is the one, in which
Water passes through tubes and flue gases around it
Tube carrying hot flue gases are immersed in a pool of water
Tubes are placed in vertical position
None of these
Which one of the following is incombustible?
H2
CCl4
C2H2
S
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