Search
.Management Sciences
Category: Heating and Welding
Which of the following insulating materials was suitable for low temperature applications ?
A. Asbestos paper
B. Diatomaceous earth
C. 80 percent magnesia
D. Cork
Induction furnaces are employed for which of the following ?
A. Heat treatment of castings
B. Heating of insulators
C. Melting aluminium
D. None of the above
is used for heating non-conducting materials?
A. Eddy current heating
B. Arc heating
C. Induction heating
D. Dielectric heating
Which of the following devices is necessarily required for automatic temperature control in a furnace ?
A. Thermostat
B. Thermocouple
C. Auto-transformer
D. Heating elements of variable resis-tance material
Hysteresis loss and eddy current loss are used in____________?
A. induction heating of steel
B. dielectric heating
C. induction heating of brass
D. resistance heating
In electric press, mica is used because it is _________ conductor of heat but/and __________ conductor of electricity?
A. bad, good
B. bad, bad
C. good, bad
D. good, good
The electrode of a direct arc furnace is made of____________?
A. tungsten
B. graphite
C. silver
D. copper
Which of the following will happen if the thickness of refractory wall of furnace is increased ?
A. Heat loss through furnace wall will increase
B. Temperature inside the furnace will fall
C. Temperature on the outer surface of furnace walls will drop
D. Energy consumption will increase
Heat is transferred simultaneously by condition, convection and radiation_____________?
A. inside boiler furnaces
B. during melting of ice
C. through the surface of the insulted pipe carrying steam
D. from refrigerator coils to freezer of a refrigerator
Induction heating takes place it which of the following ?
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
Recent Comments