A. Thermostat
B. Thermocouple
C. Auto-transformer
D. Heating elements of variable resis-tance material
A. Unity
B. Low, lagging
C. Low, leading
D. Any of the above
Direct arc furnaces have which of the following power factors ? Read More »
Heating and Welding A. The amount of heat generated can be controlled accurately
B. Heat at very high rate can be gene-rated
C. The area of the surface over which heat is produced can be accurately controlled
D. All of the above
Which of the following is an advantage of eddy current heating ? Read More »
Heating and Welding A. Annealing of metals
B. Melting of ferrous metals
C. Heating of liquids in electric kettle
D. Drying of paints and varnishes
Radiant heating is used for which of the following ? Read More »
Heating and Welding A. copper alloy
B. carbon
C. tungsten alloy
D. stainless steel alloy
For radiant heating around 2250°C, the heating elements are made of____________? Read More »
Heating and Welding A. tungsten
B. graphite
C. silver
D. copper
The electrode of a direct arc furnace is made of____________? Read More »
Heating and Welding A. Current
B. Voltage
C. Power factor
D. All of the above
In direct arc furnace, which of the following has high value ? Read More »
Heating and Welding A. voltage variation
B. thermostat
C. auto-transformer
D. series-parallel operation
In a domestic cake baking oven the temperature is controlled by________________? Read More »
Heating and Welding A. To achieve better heating
B. To increase the life of roof refractory
C. To have better stirring action
D. To reduce problem of oxidation
E. All of the above
Due to which of the following reasons it is desirable to have short arc length ? Read More »
Heating and Welding A. as an insulator
B. as a device for power factor improvement
C. for dielectric heating
D. for induction heating
In an electric press mica is used_____________? Read More »
Heating and Welding