Rain drops falling through atmospheric air attain limited terminal velocity, because of
Upward thrust due to air
Viscous force exerted by air
Surface tension effects of water
Force of gravity
Correct Answer :
B. Viscous force exerted by air
Related Questions
'Ice point' is designated on Fahrenheit temperature scale by
0°
32°
62°
212°
__________ is the most suitable lubricant for drawing mild steel wires?
Kerosene
Water
Sodium stearate
Lime water
Which one of the following is incombustible?
H2
CCl4
C2H2
S
__________ flux is used for the extraction of metal from its self fluxing ores.
No
Acid
Basic
Neutral
Water flow in the river during flood can be categorised as the __________ flow.
Unsteady uniform
Unsteady non-uniform
Steady uniform
Steady non-uniform
Which of the following are considered applications of ultrasonic testing?
Determination of elastic constant
Detection of defects in metal
Measurement of material thickness
None of the above
Two solutions A1 & A2 have pH value of 2 & 6 respectively. It implies that the solution
A1 is more alkaline than solution A2
A1 is highly acidic
A2 is very slightly acidic
Both (B) & (C)
Fine grained steels have
High brittleness
Higher tendency to distort
High ductility
None of these
For the Stoke's law to be valid in the case of a falling sphere in a fluid, the
Reynolds number (based on sphere diameter) should be < 1
Flow around the sphere should be in turbulent region
Sphere must be metallic
Fluid density should be constant
Air/fuel ratio on molar (volume) basis for combustion of methane with theoretical quantity of air with be
9.5 : 1
12.5 : 1
15.5 : 1
18.5 : 1
A solar cell converts the sunlight directly into __________ energy.
Thermal
Electrical
Mechanical
Chemical
Pick out the wrong statement about coating/electroplating of metals.
Phosphate coating is used as an excellent base for paints & enamels
Phosphate coating is less corrosion resistant than chromate coating
The base metal to be electroplated is normally made the cathode of the electrolytic cell and coating metal is made the anode
Calorising is the process of coating steel with chromium
Which of the following equipments is used for liquid dispersion?
Packed column
Venturi scrubber
Bubble cap plate column
Wetted wall column
Thermal efficiency of an internal combustion engine is around __________ percent.
8
35
65
80
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
High endurance limit of carburised machine parts is because of the fact that carburisation
Suppresses any stress concentration produced in the parts
Enhances the yield point of the material
Introduces a compressive layer on the surface
Produces a better surface finish
Which of the following forces does not act on a fluid at rest?
Viscous force
Gravity force
Hydrostatic force
Surface tension force
Carnot cycle is also termed as the constant __________ cycle in thermodynamics.
Entropy
Pressure
Volume
Heat
A fire tube boiler is limited to a maximum steam pressure of about __________ kg/cm2.
6
18
38
52
The starting of a car takes time in winter, because the
Octane number of fuel is decreased
Fuel supply for ignition is not sufficient
Vaporisation of the fuel is decreased
Pour point of fuel decreases
Pressure exerted by a liquid depends upon its
Surface tension
Density
Viscosity
Buoyancy
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
The phenomenon occurring during explosion of a hydrogen bomb is
Nuclear fission
Nuclear fusion
A combination of both nuclear fission & fusion
None of these
Electrochemical corrosion can occur, only if __________ is present in contact with metal.
Air
Oxygen
Liquid medium
Gaseous medium
Principal alloying element in Elinvar (used for making hair springs for watches) is
Copper
Aluminium
Nickel
Zinc
The minimum carbon content in steel should be __________ percent for it to respond to a hardening treatment.
0.2
0.4
0.6
0.8
Removal of non-condensable from steam or other vapour is termed as the __________ process.
Condensation
Deaeration
Scavenging
Exhaust
__________ of test specimens is not involved in any hardness testing method.
Fracture
Indentation
Wear
Scratch
Natural water contains approximately __________ percent of heavy water.
0.015
0.71
1.2
3.5
What happens, when SO2 is passed through a solution of H2S in water?
Precipitation of sulphur takes place
H2SO3 is formed
Oleum is formed
None of these