The lightest non-inflammable gas is
H2
He
Ar
O2
Correct Answer :
B. He
Related Questions
The starting of a car takes time in winter, because the
Octane number of fuel is decreased
Fuel supply for ignition is not sufficient
Vaporisation of the fuel is decreased
Pour point of fuel decreases
__________ fluid force is not considered in the Navier-Stokes equation.
Turbulent
Viscous
Gravity
Pressure
Dryness factor of steam is defined as the ratio of the mass of vapor in the mixture to the mass of the mixture. Dryness factor of steam is measured by a __________ calorimeter.
Bomb
Throttling
Junker's
Boy's
Primary designation of steel is based on its
Hardness & tensile strength
Carbon content
Iron content
Alloying elements content
Function of gear box is to
Reduce the speed
Obtain variable speed
Increase the speed
Produce high torque
A fluid is termed as the Newtonian fluid, when the shear stress is __________ the velocity gradient.
Independent of
Inversely proportional to
Directly proportional to
None of these
Brass parts with high residual tensile stress at the surface are susceptible to season cracking (i.e. spontaneous cracking occuring on exposure to atmospheric corrosion), if its zinc percentage is more than
5
10
20
35
The most suitable material of construction for a sewer to carry sewage under high pressure is
Asbestos cement
Steel
Cement concrete
Stoneware
Which one of the following is incombustible?
H2
CCl4
C2H2
S
Work required for compression of a gas contained in a cylinder is 7000 kJ. During compression, heat interaction of 3000 kJ causes the surroundings to be heated. Internal energy change of the gas during the compression is __________ kJ.
+4000
-4000
10000
-10000
What is the percentage of chromium in 18-4-1 high speed steel?
1
4
18
23
Brazing is the joining of metals
Without melting the base metal
With a non-ferrous filler
Both (A) & (B)
Neither (A) nor (B)
Silicon percentage in acid resistant cast iron is about
4
8
14
20
__________ metal is used as a bearing liner material.
Pewter
White
Babbitt
Gun
Neutrons are present in all atoms except that of
He
C
H
Ar
Property responsible for the talcum powder to cling to the skin is the
Capillary action
Adhesion
Cohesion
Surface tension
According to thermodynamic Fahrenheit scale, the fundamental interval between ice point to steam point is
180°
212°
32°
273°
Which of the following is not the commercial name of poly-methyl-methacrylate (PMMA)?
Styrofoam
Lucite
Perspex
Plexiglass
A material is capable of resisting softening at high temperature, because of its property termed as
Hot temper
Hot hardness
Fatigue
Creep
The most important consideration, while designing the refrigeration system of an aircraft is that the refrigeration system
Is as light as possible
Has very high C.O.P.
Employs minimum quantity of refrigerant
Consumer minimum horse power
The ability of tool steel to resist softening at high temperatures is termed as __________ hardness.
Red
Extended
Super
Extreme
Exposure to __________ accelerates the degradation of plastics.
Ultraviolet radiation
High atmospheric temperature
High ambient temperature
Damp atmosphere
The function of neutral flux used in the pyrometallurgy of metal extraction is to increase the __________ of the slag.
Fluidity
Basicity
Acidity
Viscosity
Unbreakable crockeries are made from __________ polymers.
Polystyrene
Melamine
Polystyrene
Polyurethane
The lightest non-inflammable gas is
H2
He
Ar
O2
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
Drills are usually made of
Cermets
High speed steel
Alloy steel
Tungsten carbide
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
The expected efficiency of a single riveted lap joint is of the order of 50%. If the thickness of the plate is increased four times, then the rivet diameter will have to be increased __________ times.
Two
Four
Six
Eight
Machinability of hard alloys and tool steels is improved by
Spheroidising
Annealing
Tempering
Normalising