The 'transition temperature' for ductile to brittle behaviour of steel increases with increase in the __________ content in steel.
Carbon
Manganese
Both 'a' nor 'b'
Neither 'a' nor 'b'
Correct Answer :
A. Carbon
Related Questions
The temperature at which the magnetic property of iron disappears (i.e., it becomes non-magnetic) and its electrical conductivity & specific heat also changes, is called the 'Curie point', which is __________ °C.
768
908
1400
1539
Principal alloying elements of cast tool alloys which have very high wear resistance & high temperature strength are
Cobalt, chromium & tungsten
Cobalt, chromium & nickel
Molybdenum, tungsten & chromium
Cobalt, zirconium & molybdenum
Cementite is in the lamellar form in the __________ phase of steel.
Martenistic
Bainitic
Pearlitic
Ferritic
The dew point of moist air becomes __________ with decrease in its relative humidity.
Less than the wet bulb temperature
More than the wet bulb temperature
More than the dry bulb temperature
Equal to wet bulb temperature
Air-petrol ratio in an automotive petrol engine is around
14 : 1
22 : 1
25 : 1
4 : 1
Consideration of the creep is the most important in case of the
Blades of gas turbine
Piston of an I. C. engine
Flywheel of steam engine
Cycle chain
Upto the critical radius of insulation, added insulation, will
Increase the heat loss
Decrease heat loss and will have no effect beyond that
Decrease heat flux
Reduce convection heat loss compared to conduction heat less
In troposphere (the weather domain), the temperature 't' at height 'h' above the sea level in metres is given by (where, temperature at sea level is 15°C and t is in °C.)
t = 15 - 0.0065 h
t = 15 + 0.0065 h
t = 0.0035 h - 15
t = 15 - 0.0035 h
Coating provided on the electrodes used in the arc welding is not expected to
Add alloying elements
Prevent electrode from contamination
Stabilise the arc
Provide protective atmosphere to weld
The capacity of a spring to store energy is called the spring form co-efficient. Stiffness of a spring is measured by the
Ability to absorb shock
Capacity to store energy
Ratio of the wire & coil diameters
Load to produce unit deflection
Referring to the periodic table of elements, it is found that with increasing atomic number. The atomic size in the same
Period increases
Period decreases
Group increases
Both 'b' & 'c'
Propulsion of rocket follows from the
Newton's second law of motion
Newton's third law of motion
Law of projectiles
Archimedes principle
Identify the correct statement.
Sphlerite is zinc oxide
The first law of the thermodynamics is stated as δE = δQ - δW
Lead can be produced in a blast furnace
T. ferrooxidans is a fungus that can be used for leaching chalcopyrite
__________ temperature remains constant during adiabatic saturation process of unsaturated air.
Dew point
Dry bulb
Wet bulb
None of these
Cold chisel & hammers are made of
High speed steel
High carbon steel
Forged steel
Mild steel
Brittleness induced due to the presence of sulphur in steel can be reduced by adding
Manganese
Magnesium
Vanadium
Copper
Notched bar test is used for testing the __________ of a material.
Impact strength
Endurance limit
Machinability
Corrosion resistance
Super conduction in metals is observed at a temperature of __________ °K.
<100
>100
About 273
About 373
The order of a chemical reaction
Can be determined only experimentally
Can be determined from the stoichiometry of the reaction
Cannot be zero
Can be fractional
Hydrogen can be
Used in I.C. engines as fuel
Liquefied & stored under cryogenic conditions
Produced by electrolysis of water
All (A), (B) & (C)
Which of the following terminology is used for the temperature at which new grains are formed in a metal?
Eutectic temperature
Lower critical temperature
Recrystallisation temperature
Upper critical temperature
Strain hardening effect in metals subjected to cold working is due to the __________ mechanism.
Slip
Fracture
Winning
Dislocation
A dense structure of grinding wheel is not used for the
Ductile material
Hard materials
Brittle materials
Finishing cuts
Thermal conductivity of a material does not depend upon its
Mass
Volume
Surface area
All 'a', 'b' & 'c'
The bolt is subjected to __________ when the nut is tightened by putting the washer beneath it.
Tension
Shear
Compression
Bending & tension
There are one octahedral void and __________ tetrahedral void in the closest packing of atoms.
One
Two
Three
None of these
The condition of diffraction from a crystal is given by
nλ = 2d Sin θ
λ = d Sin 2θ
λ = 2d Sin 2θ
nλ = d Sin θ
A cylindrical rod subjected to a tensile strain within the elastic limit undergoes a volume change. If the volume strain is equal to half the tensile strain, then the Poisson's ratio of the rod is
0
0.33
0.44
0.25
Water hammer is caused in steam carrying pipelines, because of
Partial condensation of steam
Vibration of the pipeline
High degree of superheat of steam
Its exposure to torrential rain
Pick out the wrong statement
Processing of thermosetting plastics is ideally done by injection moulding
Processing of thermoplastics is ideally done by compression moulding
Mass production of seamless pipes are done by electrical resistance welding (ERW)
Stretch forming is a process of cold drawing