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
For heating element high resistivity material is chosen to______________? Read More »
Heating and Welding 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
For intermittent work which of the following furnaces is suitable ? Read More »
Heating and Welding 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
Induction heating takes place it which of the following ? Read More »
Heating and Welding 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
By which of the following methods the temperature inside arc nace can be varied ? Read More »
Heating and Welding A. phase angle
B. frequency
C. current
D. voltage
In induction heating ___________ is abnormally high? Read More »
Heating and Welding A. oxidizing
B. deoxidising
C. reducing
D. neutral
In a resistance furnace the atmosphere is_____________? Read More »
Heating and Welding A. Water
B. Steam
C. Sold ice
D. Melting ice
Which of the following has the highest value of thermal conductivity ? Read More »
Heating and Welding 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
Heat transfer by condition will not occur when____________? Read More »
Heating and Welding