Heating & Welding(Electrical Engineering Questions ) Questions and Answers

Question 1. Properly of low temperature co-eflficient of heating element is desired due to which of the following reasons ?
  1.    To avoid initial rush of current
  2.    To avoid change in kW rating with temperature
  3.    Both (A) and (B)
  4.    Either (A) or (B)
Explanation:-
Answer: Option C. -> Both (A) and (B)
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!
Question 2. Ajax Wyatt furnace is started when____________?
  1.    it is filled below core level
  2.    it is filled above core level
  3.    it is fully empty
  4.    none of the above
Explanation:-
Answer: Option B. -> it is filled above core level
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!
Question 3. Radiations from a black body are proportional to____________?
  1.    T1
  2.    T2
  3.    T3
  4.    T*
Explanation:-
Answer: Option D. -> T*
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!
Question 4. It is desirable to operate the arc furnaces at power factor of_____________?
  1.    zero
  2.    0.707 lagging
  3.    unity
  4.    0.707 leading
Explanation:-
Answer: Option B. -> 0.707 lagging
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!
Question 5. Which of the following methods is used to control temperature in resistance furnaces ?
  1.    Variation of resistance
  2.    Variation of voltage
  3.    Periodical switching on and off of the supply
  4.    All of the above methods
Explanation:-
Answer: Option D. -> All of the above methods
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!
Question 6. Resistance variation method of temperature control is done by connecting resistance elements in_____________?
  1.    series
  2.    parallel
  3.    series-parallel connections
  4.    star-delta connections
  5.    all of the above ways
Explanation:-
Answer: Option E. -> all of the above ways
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!
Question 7. Hysteresis loss and eddy current loss are used in____________?
  1.    induction heating of steel
  2.    dielectric heating
  3.    induction heating of brass
  4.    resistance heating
Explanation:-
Answer: Option A. -> induction heating of steel
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!
Question 8. In arc furnace the function of choke is______________?
  1.    to stabilize the arc
  2.    to imprpve, power factor
  3.    to reduce severity of the surge
  4.    none of the above
Explanation:-
Answer: Option A. -> to stabilize the arc
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!
Question 9. In electric press, mica is used because it is _________ conductor of heat but/and __________ conductor of electricity?
  1.    bad, good
  2.    bad, bad
  3.    good, bad
  4.    good, good
Explanation:-
Answer: Option C. -> good, bad
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!
Question 10. In heating the ferromagnetic material by induction heating, heat is produced due to_____________?
  1.    induced current flow through the charge
  2.    hysteresis loss taking place below curie temperature
  3.    due to hysteresis loss as well as eddy current loss takingplace in the charge
  4.    none of the above factors
Explanation:-
Answer: Option C. -> due to hysteresis loss as well as eddy current loss takingplace in the charge
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!
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