Corrosion of metals cannot be prevented by its
Tempering
Chromising
Aluminising
Alloying
Correct Answer :
A. Tempering
Related Questions
__________ is used for tying the steel columns to concrete foundation.
Grouting
Eyebolt
Anchor bolts
Refractory castables
Pick out the wrong statement.
Ductile fracture of a stressed material, which exhibits a large plastic deformation is commonly caused by the formation and coalescence of voids in the necked region
Brittle fracture is caused by the propagation of pre-existing cracks in the material and involves minimum plastic deformation
Fatigue fracture of a material is always brittle in nature and takes place due to the existence of line imperfections
Brittle materials are generally tested in tension
Main constituent of bone ash is
Ammonium phosphate
Calcium phosphate
Animal charcoal
Ammonium sulphate
Photographic plates are coated with
Silver nitrate
Silver halide
Calcium silicate
Metallic silver
Catalyst used in the catalytic converter employed in automobiles to convert CO into CO2 and for complete oxidation of un-burnt hydrocarbons is
Nickel
Cobalt
Vanadium
Platinum
Which of the following is the largest quantum of pressure?
1 kg/cm2
1 bar
1 atmosphere
1 kilo Pascal
Nuclear fission of one atom of uranium-235 produces the energy equivalent to about __________ MeV.
20
200
500
2000
Nickel is a __________ material.
Ferromagnetic
Semi-conductor
Paramagnetic
Ferroelectric
The joint for soldering is supported by binding wire made of
Mild steel
Copper
Soft iron
Stainless steel
Shaft/rotor speed is most accurately measured by a
Frequency counter
Tachometer
Strobometer
Speedometer
Steam condenser tubes are made of admiralty brass, in which percentage of zinc & copper are __________ respectively.
70 & 30
30 & 70
50 & 50
90 & 10
Hydrogen in liquid steels is dissolved
As tiny gas bubbles
In the atomic form
In the ionic form
In the molecular form
Pick out the wrong statement.
Molecules with symmetrical arrangements (e.g. CH4 or CCl4) are non-polar
Generally, non-polar compounds are chemically inactive, conduct electricity poorly and do not ionise
Most of the hydrocarbons are non-polar
None of these
The excess air required for the combustion of pulverised coal is of the order of about __________ percent.
5
15
30
45
Consumable electrodes are used in the __________ welding.
Gas
Arc
Thermit
Resistance
Increase in temperature, in general results in the
Decrease in the viscosities of both liquids & gases
Increase in the viscosities of both liquids & gases
Increase in the viscosity of liquids and decrease in that of gases
Decrease in the viscosity of liquids and increase in that of gases
Speisses is a mixture of the following:
Arsenides of heavy metals
Antimonides of heavy metals
Arsenides & antimonides of heavy metals
Iron, cobalt and nickel
Eutectic reaction for iron-carbon system occurs at a temperature of __________ °C.
723
959
1147
1493
The minimum and the maximum number of members required to form a Private Limited Joint Stock Company are respectively
7 and 30
10 and 50
2 and 50
13 and 55
The friction factor for the turbulent fluid flow in a rough pipe does not depend upon the
Pipe roughness & pipe diameter
Fluid velocity
Type of flowing fluid
Both 'b' & 'c'
Chromium molybdenum steel cannot be welded using __________ welding.
Thermit
Electrical resistance
Oxy-acetylene
Any of these
Absolute zero, pressure will occur, when the molecular momentum of the system becomes zero. A liquid will cease to exist as liquid at
High vacuum
Zero pressure
0°K
Earth's centre
Temperature attained in soldering of metals is about __________ °C.
150-300
400-500
650-800
1000-1100
Spherical shape of mercury droplets is due to its
High viscosity
Low surface tension
High density
High surface tension
The mechanism which changes the value of manipulated variable in response to the output signal from the control unit is called the
Final control element
On-off control
Floating control action
None of these
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
Biological shield in a nuclear reactor is generally provided to protect against the
α-rays
β-rays
Gamma rays & neutrons
Electrons
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
Wave length of X-rays is about 1 angstrom; however it cannot pass through a sheet of
Paper
Cloth
Lead
Aluminium
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)