Spherical shape of mercury droplets is due to its
High viscosity
Low surface tension
High density
High surface tension
Correct Answer :
D. High surface tension
Related Questions
The difference between gross & net calorific values of fuel is due to the
Sensible heat carried away by the flue gases
Heat carried away by the steam from the moisture content of the fuel
Heat lost by radiation
Heat carried away by steam from the combustion of hydrogen in the fuel
Out of the following, the joint produced by __________ has the lowest strength.
Soldering
Welding
Brazing
Riveting
Optical activity is a/an __________ property.
Additive
Constitutive
Both (A) & (B)
Neither (A) nor (B)
Sacrificial anode method is used in the protection of pipelines which are buried underground. Sacrificial anode
Occurs higher in the electro-chemical series of metals
Is exemplified by magnesium plate
Is much cheaper than the cathodic base material to be guarded against corrosion
All (A), (B) & (C)
A fire tube boiler is limited to a maximum steam pressure of about __________ kg/cm2.
6
18
38
52
Sub zero treatment of steel is done to
Suppress martensite transformation
Enhance its working performance in sub zero atmosphere
Reduce the retained austenite in hardened steel
Induce temper brittleness after its hardening
Moist climate is the most favourable factor in the site selection far a
Steel plant
Textile factory
Petroleum refinery
Coke oven battery
Presence of nickel & chromium in steel does not raise its
Elastic limit
Machining properties
Ductility
Resilience
Drossing is a __________ operation.
Smelting
Dressing
Roasting
Dressing
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
When the wet steam is throttled but still remains wet at the exit of the throttle valve, then its temperature & dryness fraction respectively
Decreases & increases
Increases & increases
Increases & decreases
Decreases & decreases
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
Specific __________ is a dimensionless quantity.
Heat
Humidity
Weight
None of these
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
Which of the following has the least value of ultimate tensile strength (UTS)?
Medium carbon steel
High carbon steel
Cast iron
Wrought iron
Strain hardening effect in metals subjected to cold working is due to the __________ mechanism.
Slip
Fracture
Winning
Dislocation
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
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
There are one octahedral void and __________ tetrahedral void in the closest packing of atoms.
One
Two
Three
None of these
When an isolated thermodynamic system executes a process,
Work is done
Heat transfer takes place
Mass flow occurs across the boundary of the system
No chemical reaction takes place within the system
The only suitable method for hardening the low carbon steel is case hardening. Which of the following is a case hardening process?
Cyaniding
Sherardizing
Spheroidising
None of these
In condensers used in thermal power plants, steam is normally used in shell side and cooling water on the tube side, because of the reason that
Compared to the mass flow rate of cooling water, the rate of condensation of steam is invariably smaller
Maintaining vacuum on tube side is more difficult than that on the shell side
Water velocity can be increased conveniently to increase the overall heat transfer co-efficient because of its lower specific volume compared to steam
Condenser can act as a storage unit for condensed steam
Nickel and __________ are the alloying element added in steel to increase its toughness.
Molybdenum
Chromium
Vanadium
Silicon
In a totally irreversible isothermal expansion process for an ideal gas, ΔE = 0, ΔH = 0. Then ΔQ and ΔS will be
ΔQ = 0, ΔS=0
ΔQ = 0, ΔS = +ve
ΔQ = 0, ΔS = -ve
ΔQ = +ve, ΔS= +ve
Thermal conductivity of a material does not depend upon its
Mass
Volume
Surface area
All 'a', 'b' & 'c'
With increasing carbon percent in steel beyond 0.8%, its ultimate tensile strength (UTS) and __________ is not affected.
Impact strength
Percent elongation
Hardness
Both 'b' & 'c'
__________ is not a heat treatment process.
Cyaniding
Parkerizing
Austempering
Martempering
A high pressure boiler generates steam at a pressure greater than __________ kg/cm2.
10
30
50
80
Lead is poured into the joint between two __________ pipes.
Mild steel
Concrete
Cast iron
Asbestos cement
The usual energy consumption in electric arc furnace steel making is __________ KWh/ton of steel.
60 - 100
400 - 700
1200 -1500
2000 - 2300