In resistance heating, the material used as heating element must have high resistivity. Why?
ATo reduce the length of the heating element
BTo extend the useful life of the heating element
CTo reduce the effect of radiation
DBoth B and C
Electrical Engineering · Question Bank
Engineering Materials
117 questions · page 5 of 6. Answer in your head first, then check the solution.
What is the reason why the coreless induction furnace uses high frequency electric supply?
ATo obtain high flux density
BTo obtain high eddy current loss
CTo obtain high power factor
DAll of these
Furnaces used for cremation uses what heating methods?
AResistance heating
BDielectric heating
CArc heating
DInduction heating
Radiant heating is used for which of the following applications?
AMelting of ferrous metals
BHeating of liquids in an electric kettle
CDrying of paints and varnish
DAnnealing of metals
Which of the following instruments is used to measure the temperature inside a furnace?
AMercury thermometer
BOptical pyrometer
CDigital thermometer
DAny of these
Which of the following methods is used to control the temperature in resistance furnace?
AVariation of resistance
BVariation of voltage
CPeriodical switching on and off of the supply
DAny of these
Which of the following has the highest thermal conductivity?
AWater
BSteam
CSolid ice
DAir
Which of the following has a higher value of its thermal conductivity?
ACopper
BAluminum
CBrass
DSteel
What is the usual power factor of direct arc furnaces?
ALow and lagging pf
BLow and leading pf
CAlmost unity pf
DZero pf
Which of the following is used for heating nonconducting materials?
ADielectric heating
BArc heating
CEddy current heating
DInduction heating
In the indirect resistance heating method, maximum heat transfer occurs by using which of the following concepts?
ARadiation
BConduction
CConvection
DAll of these
Which of the following materials is preferred for transformer cores operating at microwave frequencies?
AFerrite
BSupermalloy
CSilicon steel
DCopper
Which of the following applications uses tin?
ABulb filaments
BContactors for starters
CLow current fuses
DTransducers
How do you call the ability of a material to absorb a large amount of energy?
AToughness
BDuctility
CResilience
DMalleability
A carbon resistor contains which one?
ACarbon crystals
BSolid carbon granules
CPulverized coal
DFinely divided carbon black
Brass is an alloy of which one?
ACopper and zinc
BZinc and lead
CLead and tin
DTin and silver
Which of the following is a viscoelastic material?
ACast-iron
BGraphite
CRubber
DGlass
German silver is an alloy of which one?
ACopper, manganese and nickel
BCopper, zinc and nickel
CCopper, silver and aluminum
DSilver, tin and tungsten
Which of the following applications uses a steel wire?
AOverhead telephone wires
BEarth wires
CCore wire of ACSR
DAll of these
Solder is an alloy of which of the following materials?
ANickel, copper and zinc
BSilver, copper and lead
CCopper and aluminum
DTin and lead
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