Heating and Welding

A. nickel copper
B. nichrome
C. silicon carbide
D. silver

A. reduce the length of heating element
B. increase the life of the heating element
C. reduce the effect of oxidation
D. produce large amount of heat

A. radiation
B. convection
C. conduction
D. any of the above

A. Indirect arc furnace
B. Core less furnace
C. Either of the above
D. None of the above

A. Insulating materials
B. Conducting materials which are magnetic
C. Conducting materials which are non-magnetic
D. Conducting materials which may or may not be magnetic

A. By disconnecting some of the heating elements
B. By varying the operating voltage
C. By varying the current through heating elements
D. By any of the above method

A. phase angle
B. frequency
C. current
D. voltage

A. oxidizing
B. deoxidising
C. reducing
D. neutral

A. Water
B. Steam
C. Sold ice
D. Melting ice

A. bodies are kept in vacuum
B. bodies are immersed in water
C. bodies are exposed to thermal radiations
D. temperatures of the two bodies are identical