Mho's scale of hardness, which consists of 10 standard minerals is used for the measurement of __________ hardness.
Scratch
Indentation
Dynamic
Rebound
Correct Answer :
A. Scratch
Related Questions
Which of the following is not an ore of copper?
Cryolite
Azurite
Chalcopyrite
Malachite
The ratio of thermal & electrical conductivity is same for all the metals at the same temperature; and at around room temperature, this ratio is proportional to(where, T = absolute temperature, °K)
T
1/T
T2
1/T2
Thermit welding is categorised as the __________ welding.
Forge
Fusion
Resistance
Arc
Silicon in steel
Makes it usable in almost all magnetic circuits where alternating current is used
Increases its electrical resistivity and decreases the hysteresis loss
Is present upto 5% & 4% respectively when used in transformers & motor armatures
All 'a', 'b' & 'c'
Copper deposits are found in India at the following location:
Kudremukh
Kolar
Khetri
Ramagundam
For an ideal gas, Cp - Cv is
R
-R
0
(3/2) R
Boiler draught of 10 mm water column is equivalent to
1 kgf/m2
10 kgf/m2
10 kgf/mm2
1 kgf/mm2
Hydrogen can be
Used in I.C. engines as fuel
Liquefied & stored under cryogenic conditions
Produced by electrolysis of water
All (A), (B) & (C)
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
Gross national product (GNP) means the total value of __________ in a country.
Goods produced
Gold reserve
Earning of the citizens
Taxes paid
Air-petrol ratio in an automotive petrol engine is around
14 : 1
22 : 1
25 : 1
4 : 1
On being hit with a hammer, __________ will readily fracture.
Brass
Mild steel
Cast iron
Lead
Pick out the wrong statement.
Lead can creep under its own weight at room temperature
The electrical conductivity of gold is considerably reduced by alloying additions due to the decrease in electron movement
Recrystallisation temperature decreases with decrease in strain in a cold worked metal
With increase in temperature, the electrical conductivity of intrinsic semi-conductor will increase
Cold chisels hammers are made of
High speed steel
High carbon steel
Forged steel
Mild steel
Silicon percentage in the silicon steel used for electrical appliances/equipments is
0.3-0.4
12-14
3-4
20-25
Change in volume of metals from absolute zero temperature to their melting points is
Almost same for all metals
Different for different metals
Less for low melting point metals
Less for high melting point metals
When the wavelength of incident X-rays increases, the angle of diffraction
Decreases
Increases
Remain constant
Shows no systematic variation
Which of the following rays has the least wavelength?
Ultraviolet rays
Infrared rays
Cosmic rays
X-rays
__________ is the most important element, which controls the physical properties of steel.
Manganese
Silicon
Carbon
Vanadium
The property of material, by which a given amount of energy is absorbed by it, without plastic deformation, is called
Resilience
Toughness
Ductility
Impact strength
The mechanism involved in the removal of metal in drilling operation is by
Compression
Extrusion
Shearing
Both 'b' & 'c'
Case hardening is not done by
Nitriding
Hot dipping
Electroplating
Both b & c
Use of economiser in a boiler plant reduces the fuel consumption for steam generation by about __________ percent.
1
10
30
50
The minimum and the maximum number of members required to form a Private Limited Joint Stock Company are respectively
7 and 30
10 and 50
2 and 50
13 and 55
The swift cup test evaluates the following property of a sheet metal.
Stretchability
Drawability
Bendability
None of these
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
In the acid Bessemer process, the hot metal should have the following composition.
S < 0.05% and P < 0.05%
S < 0.05% and P < 1.5%
S < 0.05% and P > 1.5%
S > 1.5% and P < 0.05%
A steam pipe is intended to be insulated with two layers of insulating materials of different thermal conductivities. For minimum heat transfer to take place
The better insulation material should be put just next to pipe (i.e., inside)
The better insulating material should be put outside
Either of the insulating material could be put on either side
Steam temperature is considered before deciding as to which insulating material is to be put inside (i.e., just next to the pipe)
__________ test can be termed as the semidestructive test.
Impact
Torsion
Hardness
Charpy
With increase in compression ratio, the volumetric efficiency of air compressor
Increases
Decreases
Remain same
May increase or decrease (depends on the suction pressure)