Brinell Hardness Number (BHN) for talc is approximately in the range of
1-5
20-30
100-150
200-250
Correct Answer :
B. 20-30
Related Questions
Hot extrusion of aluminium is done in the temperature range of __________ °C.
550-600
450-500
350-400
250-300
Powder metallurgy technique is used in the production of __________ tools.
Tungsten carbide
High carbon steel
High speed steel
Drilling
__________ property of a material is determined by the Herbert Pendulum device.
Hardness
Tensile
Toughness
Compressive
The amount of water evaporated in kg per kg of fuel burnt in a boiler is called the __________ of a boiler.
Evaporative capacity
Evaporation efficiency
Thermal efficiency
Steam load
Case hardening of a material is
Followed by tempering or carburising
Preceded by its tempering
Done to get a soft ductile interior with a very hard surface
Carried out to get extreme hardness in its core
Glass reacts with
H2SO3
HF
HNO3
K2Cr2O7
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 most suitable material of construction for a sewer to carry sewage under high pressure is
Asbestos cement
Steel
Cement concrete
Stoneware
Which of the following is not a dielectric material?
Cotton, silk and paper
Asbestos, glass, porcelain and mica
Rubber and polymeric resins
All refractory materials
Absolute zero, pressure will occur, when the molecular momentum of the system becomes zero. A liquid will cease to exist as liquid at
High vacuum
Zero pressure
0°K
Earth's centre
Milk is fat dispersed in water. It is an example of
Suspension
Emulsion
Gel
Solution
In the Bayer's process, bauxite is digested under pressure using
H2SO4
NaOH
NH3
HCl
Percentage of differential pressure lost in a Venturimeter with a tapering of 15° may be about
1
10
25
50
Consider the equilibrium A(g) + B(g) = AB(g). When the partial pressure of A is 10-2 atm, the partial pressure of B is 10-3 atm and the partial pressure of AB is 1 atm, the equilibrium constant 'K' is
10 atm-1
105 atm-1
10 (dimensionless)
105 (dimensionless)
In a drilling process, the metal is removed by both shearing & extrusion. General purpose drills are made of
Stainless steel
Mild steel
High speed steel
High carbon steel
Fahrenheit and Centigrade scales have the same readings at
-55°
-40°
-33°
-58°
Tip of the match stick contains a mixture of
K + S
K + S + K2Cr2O7
S + K2Cr2O7 + White P
None of these
__________ joint is mostly used for joining pipes carrying water at low pressure.
Nipple
Socket
Union
Bell and spigot
Projection welding & stud welding is categorised as the __________ welding.
Pressure
Thermit
Resistance
Arc
Electrometallurgical methods of metal extraction is normally used for those metals
Whose oxide/ore is not reduced by carbon
Which fall in the category of alkali & alkaline earth metals
Which stands higher in the electrochemical series of the metal
All (A), (B) & (C)
Principal alloying element in Elinvar (used for making hair springs for watches) is
Copper
Aluminium
Nickel
Zinc
Wave length of X-rays is about 1 angstrom; however it cannot pass through a sheet of
Paper
Cloth
Lead
Aluminium
A solution which resists change in its pH value on addition of acid/alkali is called the __________ solution.
Neutral
Ideal
Buffer
Zero pH
Silicon percentage in acid resistant cast iron is about
4
8
14
20
Tesla metre per ampere (T. m/A) is the unit for the measurement of
Magnetic susceptibility
Magnetic moment
Permeability of free space
Flux density
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)
Insulation of liquid surface can be achieved by __________ on top of its surface.
Floating hollow polypropylene spheres
Spraying alumina powder
Putting cement
None of these
Hydrogen can be
Used in I.C. engines as fuel
Liquefied & stored under cryogenic conditions
Produced by electrolysis of water
All (A), (B) & (C)
__________ iron is produced by the annealing of white cast iron.
Malleable
Nodular
Ductile
Grey
Alcohols are not suitable as diesel engine fuel because the cetane number of alcohols is
Very low which prevents their ignition by compression
Very high which prevents their ignition by compression
Zero
None of these