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)
Related Mcqs:
- In heating the ferromagnetic material by induction heating, heat is produced due to_____________?
A. induced current flow through the charge
B. hysteresis loss taking place below curie temperature
C. due to hysteresis loss as well as eddy current loss takingplace in the charge
D. none of the above factors - In resistance heating highest working temperature is obtained from heating elements made of_____________?
A. nickel copper
B. nichrome
C. silicon carbide
D. silver - For radiant heating around 2250°C, the heating elements are made of____________?
A. copper alloy
B. carbon
C. tungsten alloy
D. stainless steel alloy - Due to which of the following reasons it is desirable to have short arc length ?
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 - The material of the heating element for a furnace should have___________?
A. lower melting point
B. higher temperature coefficient
C. high specific resistance
D. all of the above - For heating element high resistivity material is chosen to______________?
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 - Which of the following insulating materials was suitable for low temperature applications ?
A. Asbestos paper
B. Diatomaceous earth
C. 80 percent magnesia
D. Cork - Which of the following methods of heating is not dependent on the frequency of supply ?
A. Induction heating
B. Dielectric heating
C. Electric resistance heating
D. All of the above - Which of the following is an advantage of heating by electricity ?
A. Quicker operation
B. Higher efficiency
C. Absence of flue gases
D. All of the above - Which of the following is an advantage of eddy current heating ?
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
