Plastics as a material of construction suffer from the drawback of low
Machinability
Density
Strength
Plastic deformation
Correct Answer :
C. Strength
Related Questions
Silicon percentage in silicon steel used for electrical equipments is about
1
4.0
8
14
Which of the following varies as the square root of oil pressure during atomisation of fuel oil through a pressure jet burner?
Output & fineness
Velocity
Both (A) & (B)
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
Which of the following is not the function of a volute casing provided in a centrifugal pump?
To reduce the head loss in discharge
To increase the pump efficiency
To collect liquid from the periphery of the impeller and to transmit it to the delivery pipe at constant velocity
To increase the pump discharge rate
An ideal material for making cooking vessels should have
High heat capacity
Low heat capacity
High thermal conductivity
Both (B) and (C)
Breakeven point represents the condition, when the company runs under no profit no loss condition. In break even analysis, total cost comprises of fixed cost
Only
Plus variable cost
Plus overhead cost
Plus selling expenses
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
Resistance of an electrical conductor is proportional to its (where, l = length and A = cross-sectional area of the conductor)
A
l
A2
Both 'a' & 'b'
The malleability of a material is the property by virtue of which it can be rolled or hammered into thin sheets. Which of the following materials has the maximum malleability?
Lead
Copper
Aluminium
Wrought iron
Thermit welding uses the following energy source.
Electrical energy
Chemical energy
Energy of high velocity electrons
Heat generated by friction
Hydrogen in liquid steels is dissolved
As tiny gas bubbles
In the atomic form
In the ionic form
In the molecular form
Pick out the correct combination about the role of various additives used in polymers.
Plasticiser: increases the polymer strength
Heat stabiliser: increases the maximum service temperature
Fillers: Does not affect the property of polymer but increases its weight
Lubricants: increases the flexibility of polymers
__________ furnace is generally used in the non-ferrous foundries.
Direct arc
Indirect arc
Resistance
Induction
Addition of __________ to steel does not impart hardness.
Nickel
Copper
Chromium
Silicon
Spherical shape of mercury droplets is due to its
High viscosity
Low surface tension
High density
High surface tension
The effect of friction on the flow of steam through a nozzle is to decrease the __________ of steam.
Wetness
Mass flow rate
Both 'a' & 'b'
Neither 'a' nor 'b'
Normalising of a casting does not
Induce stresses in it
Refine its grain structure
Reduce segregation
Improve its mechanical properties
The heat released by cooling one mole of copper from 400 K to room temperature (300 K) is (assume : Cp of copper is 23 J K-1mole-1)
2300 J
4600 J
230 J
2.3 × 106 J
The delivery pressure of boiler feed water pump compared to the boiler steam pressure is
Same
Slightly less
Slightly more
Much more
Dew point temperature always gives an indication of the __________ of the moist air.
Dryness
Moisture content
Coolness
Latent heat
Non-ferrous alloys used for making cutting tools need not have high
Abrasion resistance
Toughness
Red hardness
Cutting speed
When dry bulb temperature & wet bulb temperature of moist air is the same, it means that the
Partial pressure of water vapour is less than the total pressure
Humidity is < 100% & dew point temperature of air has not reached
Dew point temperature of air has not reached & air is not saturated fully
Air is fully saturated
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
Cassiterite is an ore of
Tin
Lead
Molybdenum
Chromium
Heat flow across a hollow sphere of inner radius 'r1' and outer radius 'r2' is directly proportional to
(r2 - r1)/r1. r2
r1. r2/(r2 - r1)
(r2 + r1)/r1. r2
r1. r2/(r2 + r1)
Pick out the wrong statement.
A soft magnetic material should have high permeability and small area of hysteresis loop
Poisson's ratio of high melting point metals is more than unity
Solders generally melt at less than 185°C
Steel produced by B.O.F process is ideally suited for manufacturing flat product
Use of water as a manometric liquid suffers from the disadvantage of its
Low vapour pressure
Corrosive nature
High vapour pressure
High boiling point
For a spontaneous natural process at constant temperature and pressure, the free energy of the system always
Increases
Decreases
Remain constant
Increases to a maximum before decreasing
The amount of different substances produced, when the same quantity of electricity is passed through different solutions are proportional to their
Equivalent weight
(Equivalent weight)2
Molecular weight
(Molecular weight)2
Calorific value of __________ are almost same.
Lignite & anthracite coal
Lignite & coal gas
Petrol & diesel
Coal gas & natural gas