Lead pencil contains
Graphite
Lead sulphide
Lead
Both (B) & (C)
Correct Answer :
A. Graphite
Related Questions
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
__________ remains constant during the adiabatic cooling of moist air.
Wet bulb temperature
Dry bulb temperature
Relative humidity
Specific humidity
Referring to the periodic table of elements, it is found that with increasing atomic number. The atomic size in the same
Period increases
Period decreases
Group increases
Both 'b' & 'c'
Coating provided on the electrodes used in the arc welding is not expected to
Add alloying elements
Prevent electrode from contamination
Stabilise the arc
Provide protective atmosphere to weld
Uniform ramming of sand in green sand moulding process leads to
Reduced chance of gas porosity
Greater dimensional stability of the casting
Uniform flow of molten metal into the mould cavity
Less sand expansion type of casting defect
For a small scale toy factory, the fixed cost per month is Rs. 5000/-. The variable cost per toy is Rs. 20 and sales price is Rs. 30 per toy. The break even production per month will be __________ toys.
250
500
1000
3000
A thin, flat & square plate measuring 2 m × 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will remain constant at 30°C, if the convective heat transfer co-efficient is __________ W/m2 °C.
50
100
150
200
Which of the following is not a charge material for cupola?
Limestone
Iron scrap
Iron ore
Pig iron
Quartz is a __________ material.
Diamagnetic
Ferromagnetic
Ferroelectric
Piezoelectric
The order of a chemical reaction
Can be determined only experimentally
Can be determined from the stoichiometry of the reaction
Cannot be zero
Can be fractional
According to maximum shear stress failure criterion, yielding in material occurs, when the maximum shear stress is equal to __________ times the yield stress.
0.5
2
√2
√3/2
Gross national product (GNP) means the total value of __________ in a country.
Goods produced
Gold reserve
Earning of the citizens
Taxes paid
What is the critical radius of insulation (cms) for a metallic cylinder, if the convective heat transfer co-efficient with the ambient atmosphere is 5 W/m2. °K? Thermal conductivity of metal and insulation material are 40 and 0.1 W/m.°K respectively.
2
8
10
40
The co-ordination number in simple cubic structure is
4
6
8
12
Dry saturated steam can be converted into superheated steam by
Increasing its cross-sectional area of flow
Passing it through a pressure reducing valve
Forcing it downwards through a vertical tube
None of these
Normalising of a casting does not
Induce stresses in it
Refine its grain structure
Reduce segregation
Improve its mechanical properties
At absolute zero temperature, for any reaction involving condensed phases
Δ G° = 0 , Δ H° = 0
Δ H° = 0 , Δ S° = 0
Δ S° = 0 , Δ E° = 0
Δ S° = 0 , Δ Cp° = 0
In case of a, centrifugal pump, the ratio h1/h2 is termed as the __________ efficiency (where, h1 = actual measured head & h2 = head imparted to the fluid by impeller).
Mechanical
Overall
Volumetric
Impeller
Tumbling is the process of improving the __________ of the materials/parts.
Surface finish
Fatigue limit
Creep limit
Surface cleanliness
The process of removal of scale formed during hot rolling of steel is termed as
Descaling
Shot blasting
Pickling
Skimming
The atmospheric temperature during melting of ice/snow (in the atmosphere)
Decreases
Increases
Remain same
May increase or decrease; depends on the altitude where snow melts
A fluid is termed as the Newtonian fluid, when the shear stress is __________ the velocity gradient.
Independent of
Inversely proportional to
Directly proportional to
None of these
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'
At 100% relative humidity, the dew point temperature of moist air is
Less than the wet bulb temperature
More than the wet bulb temperature
Equal to the wet bulb temperature
Equal to the ambient temperature
Lap joints are preferred over butt joints in soldering/brazing, because these joints are
Weaker in tension but stronger in shear
Weaker in shear but stronger in tension
Stronger in both shear and tension
The lap joints are easily made
Fatigue limit improvement by over stressing the metal by successively increasing the load is called coaxing. In fatigue failure, the material fails
Below the yield point
Above the yield point
Below the elastic limit
At the elastic limit
The most important function of a washer is to provide bearing area and washers are normally specified by their hole diameters. The diameter of washer as compared to the nut is
More
Less
Same
More but less than the diameter of bolt
Which of the following hardness tests does not measure the indentation hardness of metals and alloys?
Vickers hardness test
Shore scleroscope test
Brinell hardness test
Rockwell hardness test
What is the percentage of chromium in 18-4-1 high speed steel?
1
4
18
23
Ferromagnetic materials owe their properties to __________ inner sub-shells.
Completely filled
Partially filled
Equally filled
Vacant