Addition of __________ to steel does not help in improving its machinability.
Sulphur
Silicon
Lead
Phosphorous
Correct Answer :
B. Silicon
Related Questions
Stresses encountered in the metal forming processes are less than the __________ of the material.
Fracture strength
Yield strength
Elastic limit
Limit of proportionality
Often earing defects are found during deep drawing operation, because the
Surface finish of the sheet is poor
Sheet material has been given substantial spring back
Starting sheet has planer anisotropy due to its texture
Starting sheet has normal anisotropy due to its texture
With increase in steam pressure, its specific volume decreases
Rapidly first and then slowly
Linearly
Slowly first and then rapidly
Exponentially
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 units of the rate constant for a second order reaction are
In a furnace with heating element temperature at 1700°C, the dominant mechanism of heat transfer will be
Conduction
Radiation
Natural convection
Forced convection
Oxide layer formed on the non-ferrous metal surface after its annealing is
Removed by acid pickling
Hammered into the surface
Removed with coarse emery cloth
Left as such to protect the surface
Oxygen cylinders used for autogenous (cutting/welding) purposes are
Seamless & made of steel
Heat treated before use
Made by sand casting
Welded steel cylinders
The 'laughing gas' is
Nitrous oxide
Nitric oxide
Nitrogen trioxide
Nitrogen pentoxide
The bolt is subjected to __________ when the nut is tightened by putting the washer beneath it.
Tension
Shear
Compression
Bending & tension
Melting point & boiling points of liquid oxygen are respectively - 218.8°C & - 183°C, while the same for liquid nitrogen is - 210°C & - 195.8°C respectively. The difference in melting points of liquid oxygen & liquid nitrogen is not equal to 8.8
°C
°F
°K
°R
Dies for wire drawing are generally made of
Mild steel
Stainless steel
Carbides
High carbon steel
Colour comparator is used to measure the
pH value
Electrode potential
Colour intensity
None of these
Factor of safety is the ratio of the __________ stress to the working stress.
Tensile
Compressive
Yield
Bearing
Electrical conductivities of semi-conductors are of the order of __________ ohm/cm.
10-3
103
10-15
1015
A gas which is collected over water becomes moistened due to water vapor, exerts its own partial pressure at the gas temperature, which is termed as its
Aqueous tension
Saturated humidity
Vapor pressure
Absolute humidity
In a good rimming steel
Carbon and silicon should be low
Silicon should be low but carbon should be high
Both silicon & carbon should be high
Silicon should be high but carbon should be low
The activity of pure hydrogen gas at 1000°C and 5 atm pressure
Is always less than 1
Is always greater than 1
Can be 5
Depends on the choice of the standard state
The heat of neutralisation remains constant, when there is a reaction between dilute solutions of strong
Base and strong acid
Base and weak acid
Acid and weak base
None of these
Uniform ramming of sand in green sand moulding process leads to
Reduced chance of gas porosity
Greater dimensional stability of the casting
Uniform flow of molten metal into the mould cavity
Less sand expansion type of casting defect
Gage pressure within a spherical droplet of a fluid is 'p'. What will be gage pressure within a bubble of the same size & of the same fluid?
p
2 p
0.5 p
0.25 p
Pick out the wrong statement.
Geothermal energy is a non-conventional source of energy
Mass is converted into energy in both nuclear fission & fusion reaction
Inhalation of mercury vapour is not harmful for human beings
Inhalation of arsenic causes cancer
__________ is the most suitable lubricant for drawing mild steel wires?
Kerosene
Water
Sodium stearate
Lime water
A pycnometer is used for the measurement of
Flow rate of molten metal
Specific gravity of a liquid
Composition of alloys
Concentration of a solution
The substance used as a smoke screen in warfare is
C2H2
SiCl4
P2O5
PCl5
Which of the following is not a ferromagnetic material?
Nickel
Cobalt
Aluminium
Iron
A material being tested for endurance strength is subjected to the __________ load.
Impact
Completely reversed
Dynamic
Static & dynamic
For a small scale toy factory, the fixed cost per month is Rs. 5000/-. The variable cost per toy is Rs. 20 and sales price is Rs. 30 per toy. The break even production per month will be __________ toys.
250
500
1000
3000
A semi-conductor is damaged & behaves like a conductor, on passing a strong electric current through it, because it heats up the crystals & breaks the covalent bonds resulting in __________ electrons.
Lack of free
Excess of
Decrease in
None of these
An alloy of Fe - 0.4 % C is
Cast iron
Hypo-eutectoid steel
Hyper-eutectoid steel
Eutectoid steel