Q.1
In electric press, mica is used because it is _______ conductor of heat but/and________ conductor of electricity.
  • bad, good
  • bad, bad
  • good, bad
  • good, good
Q.2
Induction heating takes place in which of the following?
  • Insulating materials
  • Conducting materials which are magnetic
  • Conducting materials which are nonmagnetic
  • Conducting materials which may or may not be magnetic
Q.3
Induction furnaces are employed for which of the following?
  • Heat treatment of castings
  • Heating of insulators
  • Melting aluminium
  • None of the above
Q.4
Radiant heating is used for which of the following?
  • Annealing of metals
  • Melting of ferrous metals
  • Heating of liquids in electric kettle
  • Drying of paints and varnishes
Q.5
The temperature inside a furnace is usually measured by which of the following?
  • Optical pyrometer
  • Mercury thermometer
  • Alcohol thermometer
  • Any of the above
Q.6
By the use of which of the following, high frequency power supply for induction furnaces can be obtained?
  • Coreless transformers
  • Current transformers
  • Motor-generator set
  • Multiphase transformer
Q.7
In a resistance furnace the atmosphere is
  • Oxidizing
  • Deoxidizing
  • Reducing
  • Neutral
Q.8
In an electric press mica is used
  • As an insulator
  • As a device for power factor improvement
  • For dielectric heating
  • For induction heating
Q.9
The electrode of a direct arc furnace is made of
  • Tungsten
  • Graphite
  • Silver
  • Copper
Q.10
Which of the following heating methods has maximum power factor?
  • Arc heating
  • Dielectric heating
  • Induction heating
  • Resistance heating
Q.11
Heat transfer by condition will not occur when
  • Bodies are kept in vacuum
  • Bodies are immersed in water
  • Bodies are exposed to thermal radiations
  • Temperatures of the two bodies are identical
Q.12
For heating element high resistivity material is chosen to
  • Reduce the length of heating element
  • Increase the life of the heating element
  • Reduce the effect of oxidation
  • Produce large amount of heat
Q.13
The material of the heating element for a furnace should have
  • Lower melting point
  • Higher temperature coefficient
  • High specific resistance
  • All of the above
Q.14
Radiations from a black body are proportional to
  • T
  • T2
  • T3
  • T4
Q.15
Properly of low temperature co-eflficient of heating element is desired due to which of the following reasons?
  • To avoid initial rush of current
  • To avoid change in kW rating with temperature
  • Both (A) and (B)
  • Either (A) or (B)
Q.16
In induction heating __________ is abnormally high.
  • Phase angle
  • Frequency
  • Current
  • Voltage
Q.17
welding methods where fusion is achieved by heating the materials to be joined using an electric arc(s). This may be done with or without filler material.
  • flux
  • solldering
  • Brazing
  • mig Welding
  • arc welding
Q.18
The temperature that needs to be reached to allow metal to begin to liquefy.
  • tempering
  • soldering
  • liquidus
  • melting point
  • solidus
0 h : 0 m : 1 s