Electrical Heating MCQ Part 2
Q1. 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 [Correct Answer]
D. good, good
Answer : C
Q2. Direct arc furnaces have which of the following power factors ?
A. Unity
B. Low, lagging [Correct Answer]
C. Low, leading
D. Any of the above
Answer : B
Electrical Heating MCQ Part 2
Q3 . ____ is used for heating non-conducting materials.
A. Eddy current heating
B. Arc heating
C. Induction heating
D. Dielectric heating [Correct Answer]
Answer : D
Q4. Induction heating process is based on which of the following principles ?
A. Thermal ion release principle
B. Nucleate heating principle
C. Resistance heating principle
D. Electro-magnetic induction principle [Correct Answer]
Answer : D
Q5. By the use of which of the following, high frequency power supply for induction furnaces can be obtained ?
A. Coreless transformers
B. Current transformers
C. Motor-generator set [Correct Answer]
D. Multi-phase transformer
Answer : C
Electrical Heating MCQ Part 2
Q6. 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 [Correct Answer]
Answer : E
Electrical Heating MCQ Part 2
Q7. Resistance variation method of temperature control is done by connecting resistance elements in
A. series
B. parallel
C. series-parallel connections
D. star-delta connections
E. all of the above ways [Correct Answer]
Answer : E
Q8. In direct arc furnace which of the following has high value ?
A. Current [Correct Answer]
B. Voltage
C. Power factor
D. All of the above
Answer : A
Electrical Heating MCQ Part 2
Q9. 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 [Correct Answer]
D. All of the above
Answer : C
Q10. Which of the following insulating materials is suitable for low temperature applications?
A. Asbestos paper
B. Diatomaceous earth [Correct Answer]
C. 80 percent magnesia
D. Cork
Answer : B
Electrical Heating MCQ Part 2
Q11. Induction furnaces are employed for which of the following?
A. Heat treatment of castings [Correct Answer]
B. Heating of insulators
C. Melting aluminium
D. None of the above
Answer : A
Q12. In the indirect resistance heating method, maximum heat-transfer takes place by
A. radiation [Correct Answer]
B. convection
C. conduction
D. any of the above
Answer : A
Electrical Heating MCQ Part 2
Q13. Hysteresis loss and eddy current loss are used in
A. induction heating of steel [Correct Answer]
B. dielectric heating
C. induction heating of brass
D. resistance heating
Answer : A
Q14. When a body reflects entire radiation incident on it, then it is known as
A. white body [Correct Answer]
B. grey body
C. black body
D. transparent body
Answer : A
Q15. A non-dimensional number generally associated with natural convection heat transfer is
A. Prandt1 number
B. Grashoff number [Correct Answer]
C. Pecekt number
D. Nusselt number
Answer : B
Electrical Heating MCQ Part 2
