Co-efficient of performance of a Carnot cycle refrigerator operating between - 23°C and + 27°C is
3
5
0.5
1.5
Correct Answer :
B. 5
Related Questions
Flue gases pass through the following boiler accessories in a high pressure natural circulation boiler.
A. Induced draft fan
B. Economiser
C. Air preheater
D. Steam superheater Which of the following gives the correct sequence of flow of the flue gases through the above mentioned boiler accessories?
A, C, B, D
D, B, C, A
D, C, B, A
D, A, B, C
Which of the following gases cause global warming?
Carbon monoxide
Carbon dioxide
Nitrogen
Ozone
Even though heat transfer co-efficient in boiling liquids is large, use of fins is advantageous, when the entire surface is exposed to __________ boiling.
Film
Nucleate
Transition
All modes of
Lead is poured into the joints between two __________ pipes.
Cast iron
Steel
Concrete
Plastic
A high pressure boiler generates steam at a pressure greater than __________ kg/cm2.
10
30
50
80
In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the
Range is 15°F
Approach is 10°F
Both (A) & (B)
Neither (A) nor (B)
__________ test can be termed as the semidestructive test.
Impact
Torsion
Hardness
Charpy
Which of the following mainly decides the current to be employed is arc welding?
Electrode size
Plate thickness
Voltage across the arc
Welded portion length
Fire refining process is employed in case of
Tin
Copper
Zinc
Aluminium
Out of the following, the joint produced by __________ has the lowest strength.
Soldering
Welding
Brazing
Riveting
Pick out the wrong statement.
The equivalent stiffness of two springs (of equal stiffness 'S') in series is S/2 while in parallel is 2S
For a helical spring, deflection is proportional to D3 (D = mean coil diameter) or d4 (d = wire diameter)
Crushing load or columns is less than the buckling load
Modulus of resilience is proportional to (stress at elastic limit)2
Starting friction is low in case of the __________ lubrication.
Boundary
Hydrodynamic
Hydrostatic
Mixed/semi-fluid
Volumetric composition of flue gas analysed with the Orsat apparatus is : CO2 = 12%, O2 = 8%, CO = nil, N2 = 80%. This flue gas composition indicates that
Pure oxygen has been used for combustion
Nitrogen percentage in the fuel is very high
Excess air has been used for combustion
Hydrogen is not present in the fuel
The most commonly used moderator in nuclear power plants is
Graphite
Light water
Heavy water
Beryllium
The most important requirement for aluminium industry is the availability of cheap
Ore
Electrical power
Labour
Abundant water
Which of the following contributes maximum as main source of sulphur in the blast furnace charge?
Sinter
Coke
Iron ore
Limestone
Out of the following, the best material capable of withstanding shock & vibration without the danger of cracking is
Malleable iron
Grey cast iron
Chilled cast iron
White cast iron
Powder metallurgy is used to produce
High precision components with complex cavities and sharp features
Components of large size
Porosity free components
Components of such alloys whose constituents do not form alloys readily
In chemical dehumidification process
Wet bulb temperature increases
Dry bulb temperature remains constant
Dew point temperature increases
Dry bulb temperature increases
Pick out the wrong statement.
Molecules with symmetrical arrangements (e.g. CH4 or CCl4) are non-polar
Generally, non-polar compounds are chemically inactive, conduct electricity poorly and do not ionise
Most of the hydrocarbons are non-polar
None of these
Percentage of argon (by volume) in dry atmospheric air is about
0.09
0.3
0.57
0.94
Mho's scale of hardness, which consists of 10 standard minerals is used for the measurement of __________ hardness.
Scratch
Indentation
Dynamic
Rebound
Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the __________ temperature of air.
Wet bulb
Dry bulb
Saturation
Dew point
Oxyacetylene reducing flame is used while carrying out welding on
Alloy steel
Grey cast iron
Mild steel
High carbon steel
'Ice point' is designated on Fahrenheit temperature scale by
0°
32°
62°
212°
The softness or hardness of a grinding wheel depends upon the type & amount of bonding material used. For general purpose cutter grinding __________ grinding wheel is normally used.
Hard
Soft
Silicon carbide
Aluminium oxide
With increase in impurities in metals, their corrosion resistances
Increase
Decrease
Remain same
May increase or decrease; depending on the type of metal
During sensible heating of humid air
Relative humidity increases
Dew point remains constant
Dry bulb & wet bulb temperature increases
Both 'b' & 'c'
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
__________ furnace is generally used in the non-ferrous foundries.
Direct arc
Indirect arc
Resistance
Induction