With increase in compression ratio, the volumetric efficiency of air compressor
Increases
Decreases
Remain same
May increase or decrease (depends on the suction pressure)
Correct Answer :
A. Increases
Related Questions
The most abundant metal present in the earth's crust is;
Iron
Copper
Titanium
Aluminium
Out of the following __________ iron has the best capability to bear sudden & excessive shocks.
White
Cast
Wrought
Pig
The kinematic viscosity (in stoke) and the absolute/dynamic viscosity (in poise) are the same for __________ at room temperature.
Air
Water
Mercury
Alcohol
An ideal material for making cooking vessels should have
High heat capacity
Low heat capacity
High thermal conductivity
Both (B) and (C)
Strain hardening effect in a metal subjected to cold working is due to the __________ mechanism.
Fracture
Dislocation
Slip
Twinning
Which of the following mainly decides the current to be employed is arc welding?
Electrode size
Plate thickness
Voltage across the arc
Welded portion length
Secondary hardening in steels arises out of the
Precipitation of fine alloy carbides at high temperatures
Refinement of ferrite grain size by working
Decomposition of retained austenite upon heat treatment
Precipitation of complex inter-metallic upon heat treatment
__________ furnace is generally used in the non-ferrous foundries.
Direct arc
Indirect arc
Resistance
Induction
Propulsion of rocket follows from the
Newton's second law of motion
Newton's third law of motion
Law of projectiles
Archimedes principle
Speisses is a mixture of the following:
Arsenides of heavy metals
Antimonides of heavy metals
Arsenides & antimonides of heavy metals
Iron, cobalt and nickel
Corrosion of metals cannot be prevented by its
Tempering
Chromising
Aluminising
Alloying
Steel rods are normally used for concrete reinforcement because concrete and steel have almost equal
Tensile strength
Compressive strength
Young's modulus
Thermal co-efficient of expansion
__________ are normally subjected to sub-zero treatment.
Highly stressed parts
Gauges or precision parts
Cold rolled sheets
Non machinable materials
Which of the following relationships is correct for relating the three elastic constants of an isotropic elastic material (where, E = Young's modulus, G = Modulus of rigidity or shear modulus v = Poisson's ratio)?
E = 2G (1 + v)
E = G (1 + v)
E = G (1 + v)/2
E = 2G (1 + 2v)
Triple point of water is
0°F
492°R
0°K
-273°C
The thermodynamic law, 
= constant, is not followed by the
Free expansion of an ideal gas
Adiabatic expansion of steam in turbine
Adiabatic compression of air
Ideal compression of air
Tempering of a material does not improve its
Machinability
Toughness
Internal stress level
Softness
Surface tension of a liquid
Is due to intermolecular forces of cohesion
Decreases with rise in temperature
Is responsible for the spherical shape of an isolated liquid drop
All (A), (B) & (C)
Annealing of cast iron
Softens it to facilitate machining
Decreases the free carbon
Increases the strength
None of these
__________ metal is used as a bearing liner material.
Pewter
White
Babbitt
Gun
Highest cutting speed is achieved by the __________ tool material.
High speed steel
Carbide
Cast alloy
Plain carbon steel
Most of the phosphorous present in the blast furnace burden enters into
Hot metal
Flue gases
Slag
Refractory lining
Euler number is defined as the ratio of inertia force to __________ force.
Pressure
Elastic
Gravity
Viscous
Pick out the wrong statement.
Cold cracking of a weld is due to the presence of hydrogen gas in the weld
True stress is given by, σ = σE (1 + εE), where σE and εE are engineering stress and engineering strain respectively
Phosphorous can be easily recovered in the iron blast furnace
High residual stress at the surface is beneficial for fatigue properties of a material
Pick out the wrong statement.
For a pressure vessel to be classified as 'thin vessel', the ratio of wall thickness to mean radius is less than 0.1
For calculating forces and efficiency of riveted joint, either rivet diameter or rivet hole diameter is used in case of pressure vessel and in structural work
Longitudinal joint is normally made butt joint to maintain the circularity of the vessel
Maximum diameter of the opening provided in a pressure vessel, which does not require any compensation is 200 mm
Percentage of argon (by volume) in dry atmospheric air is about
0.09
0.3
0.57
0.94
Hydrogen can be
Used in I.C. engines as fuel
Liquefied & stored under cryogenic conditions
Produced by electrolysis of water
All (A), (B) & (C)
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
To improve the machinability of steel, it is generally subjected to
Spheroidising
Tempering
Normalising
Annealing
The property of material, by which a given amount of energy is absorbed by it without plastic deformation, is called the
Resilience
Toughness
Ductility
Impact strength