It is desirable to operate the arc furnaces at power factor of_____________?

Properly of low temperature co-eflficient of heating element is desired due to which of the following reasons ?

A. To avoid initial rush of current

B. To avoid change in kW rating with temperature

C. Both (A) and (B)

D. Either (A) or (B)

Ajax Wyatt furnace is started when____________?

A. it is filled below core level

B. it is filled above core level

C. it is fully empty

D. none of the above

Radiations from a black body are proportional to____________?

A. T1

B. T2

C. T3

D. T*

Which of the following methods is used to control temperature in resistance furnaces ?

A. Variation of resistance

B. Variation of voltage

C. Periodical switching on and off of the supply

D. All of the above methods

In arc furnace the function of choke is______________?

A. to stabilize the arc

B. to imprpve, power factor

C. to reduce severity of the surge

D. none of the above