All the atoms of the world comprise of electrons, proton & neutron except that of __________ atom in which neutron is absent.
Deuterium
Hydrogen
Neon
Helium
Correct Answer :
B. Hydrogen
Related Questions
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)
The maximum thickness of the metal which can be welded using ultrasonic welding is __________ mm.
0.5
3
10
25
A fire tube boiler is limited to a maximum steam pressure of about __________ kg/cm2.
6
18
38
52
On oscilloscope screen for dynamic measurement, lissajous diagram is normally used to determine the __________ of the input signal.
Frequency
Amplitude
Damping
None of these
The main reducing agent in iron blast furnace is
Carbon dioxide
Carbon monoxide
Oxygen
Air
Powder metallurgy technique is used in the production of __________ tools.
Tungsten carbide
High carbon steel
High speed steel
Drilling
Brazing filler metal used for joining steel plates
Melts below the melting points of base metals
Melts below 300°C
Is copper phosphorous alloy
Is copper
Steel & cast iron pipes are produced by __________ casting.
Slush
Die
Investment
True centrifugal
Satellites burn off during re-entry to earth's atmosphere, because of the
Combustion with air
Gravitational pull by earth
Friction with earth's atmosphere
Loss in weight of the satellite
Out of the following, maximum temperature drop for a given heat flow & for the same thickness will be in the case of
Steel
Glass wood
Copper
Fireclay bricks
Which of the following is not the commercial name of poly-methyl-methacrylate (PMMA)?
Styrofoam
Lucite
Perspex
Plexiglass
Which of the following materials does not form adherent oxide film on surface?
Copper
Nickel
Aluminium
Gold & silver
A material is capable of resisting softening at high temperature, because of its property termed as
Hot temper
Hot hardness
Fatigue
Creep
The leaching solvent used in Baeyer's process for the purification of bauxite is
Ammonium hydroxide
Sodium carbonate
Sodium hydroxide
Ammonium carbonate
Function of gear box is to
Reduce the speed
Obtain variable speed
Increase the speed
Produce high torque
The behaviour of a metal specimen, which when plastically strained in tension reduces its yield stress in compression and vice versa; is termed as the
Work hardening
Bauschinger effect
Creeping effect
Stress recovery effect
The noble metals
Are exemplified by Na, K and Li
Do not resist corrosion very strongly
Are the lowermost in the electro-chemical series of metals
None of these
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'
The most important function of a washer is to provide bearing area and washers are normally specified by their hole diameters. The diameter of washer as compared to the nut is
More
Less
Same
More but less than the diameter of bolt
__________ fluid force is not considered in the Navier-Stokes equation.
Turbulent
Viscous
Gravity
Pressure
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
For grinding of softer materials, the grinding wheel should have __________ grain size.
Finer
Coarser
Medium
Any type of
Between 230 and 370°C, blue brittleness is caused in mild steel because of the
Immobility of dislocation
Strain-ageing
Increase in Young's modulus
Strain hardening
Exposure to __________ accelerates the degradation of plastics.
Ultraviolet radiation
High atmospheric temperature
High ambient temperature
Damp atmosphere
Liquor poisoning generally occurs due to the presence of __________ in it.
Ethyl alcohol
Impurities
Methyl alcohol
Carbonic acid
Temperature profile along the length of a gasgas counter flow heat exchanger is correctly represented by
According to thermodynamic Fahrenheit scale, the fundamental interval between ice point to steam point is
180°
212°
32°
273°
Carbide tipped cutting tools are manufactured by powder metallurgy techniques and have a composition of
90% tungsten carbide and 10% cobalt
70% aluminium oxide & 30% silica
30% nickel, 15% chromium & 55% tungsten
65% tungsten & 35% zirconium
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
A steam carrying pipeline is insulated with two layers of insulating materials with the inferior insulation material forming the inner part. If the two insulating layers are interchanged, the heat conducted will
Increase
Decrease
Remain unaffected
May increase or decrease; depends on the thickness of each layer