__________ is not used as the control rod material in a nuclear reactor.
Cobalt
Hafnium
Cadmium
Boron
Correct Answer :
A. Cobalt
Related Questions
Nickel and __________ are the alloying element added in steel to increase its toughness.
Molybdenum
Chromium
Vanadium
Silicon
The temperature at which the magnetic property of iron disappears (i.e., it becomes non-magnetic) and its electrical conductivity & specific heat also changes, is called the 'Curie point', which is __________ °C.
768
908
1400
1539
The refractory lining of the bottom in a basic electric arc furnace is made of
Silica
Alumina
Magnesia
Fireclay
A particle is settling in a liquid under Stokesian conditions. The free falling velocity of the particle is proportional to
√(Particle diameter)
Particle diameter
(Particle diameter)2
(Particle diameter)3
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)
In the acid Bessemer process, the hot metal should have the following composition.
S < 0.05% and P < 0.05%
S < 0.05% and P < 1.5%
S < 0.05% and P > 1.5%
S > 1.5% and P < 0.05%
A solid aluminium ball, when quenched in a water bath maintained at 40°C, cools down from 550°C to 450°C in 20 seconds. The expected temperature of the ball after next 20 seconds may be about __________ °C.
370
340
320
300
In a good rimming steel
Carbon and silicon should be low
Silicon should be low but carbon should be high
Both silicon & carbon should be high
Silicon should be high but carbon should be low
The majority charge carriers in p-type silicon are
Free electrons
Ions
Conduction electrons
Holes
Alumina, silica, lime and iron oxide are the basic raw material for the manufacture of Portland cement. The component of Portland cement which first hardens is
Projection welding & stud welding is categorised as the __________ welding.
Pressure
Thermit
Resistance
Arc
Lead pencil contains
Graphite
Lead sulphide
Lead
Both (B) & (C)
Yield strength of a polycrystalline metal with an average grain size d, is proportional to
d1/2
d-1/2
d
d-1
The kinematic viscosity (in stoke) and the absolute/dynamic viscosity (in poise) are the same for __________ at room temperature.
Air
Water
Mercury
Alcohol
Parallel straight line pattern of temperature distribution for both hot and cold fluids is observed in case of heat exchanger of the type
Parallel flow with equal heat capacities
Counter flow with equal heat capacities
Counter flow with unequal heat capacities
Parallel flow with unequal heat capacities
In a boundary layer developed along the flow, the pressure decreases in the downstream direction. The boundary layer thickness in this case will
Decrease gradually
Increase gradually
Increase rapidly
Remain constant
Which of the following metals reacts violently with water?
Mercury
Sodium
Calcium
Magnesium
Alcohols are not suitable as diesel engine fuel because the cetane number of alcohols is
Very low which prevents their ignition by compression
Very high which prevents their ignition by compression
Zero
None of these
Corona discharge is related to the operation of a/an
Induction motor
Electrostatic precipitator
Fast breeder reactor
Magneto hydrodynamic generator (MHD)
If the demand for an item is trebled and the order cost is reduced to one third, then the economic order quantity
Is trebled
Remains unchanged
Decreases by a factor of 3
Decreases by a factor of 1/3
With increase in temperature, the surface tension of water
Increases
Decreases
Remain constant
Increases linearly
The product out from a cupola is called
Wrought iron
Pig iron
Cast iron
None of these
Water-tube boiler is the one, in which
Water passes through tubes and flue gases around it
Tube carrying hot flue gases are immersed in a pool of water
Tubes are placed in vertical position
None of these
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
Which of the following materials has the poorest electrical conductivity?
Carbon
Aluminium
Silver
Stainless steel
The two elements required to form substitutional solid solution should not have
Same crystalline structure
Same valency
Widely differing electronegativity
Same atomic sizes
The elastic strain energy of a unit length of an edge dislocation as compared to that of a screw dislocation is
More
Equal
Less
Double
If the head is doubled in & centrifugal pump, the power required will increase in the ratio of
23
23/2
25/2
21/3
Powder metallurgy technique is used in the production of __________ tools.
Tungsten carbide
High carbon steel
High speed steel
Drilling
__________ is used as a material of construction for the blade of power saw.
Wrought iron
Stainless steel
Mild steel
High speed steel