Q.16 Which of the following is/are electrical properties of an arc?
A. Blow effect at edges
B. Blow effect due to ground currents in the work-piece
C. Arc stability and Arc blow
D. all of the above
Ans.: D
Q.17 The estimated temperature of the core of the arc is about ___
A. 500° C
B. 6000° C
D. 10000° C
D. 5000° C
Ans.: B
Q.18A depression due to force of the arc formed in the molten metal is called___
A. crater
B. molten pool
C. plasma
D. all of the above
Ans.: A
Q.19 During welding process_________ is exposed to atmosphere.
A. the globules of molten electrode wire
B. work piece to be weld
C. Both A and B
D. medium in which welding process is made
Ans.: C
Q.19 Which of the following atmospheric action is to be occurs during welding process?
A. oxidizing action
B. Nitriding action
C. Both A and B
D. carbon mono oxide is evolved
Ans.: C
Q.20 Which of the following reduce the ductility of the weld?
A. Nitrides
B. Oxides
C. carbon dioxide
D. carbon monoxide
Ans.: B
Q.21 Nitrides produces _____in the weld deposit.
A. ductility
B. luster
C. embrittlement
D. all of the above
Ans.: C
Q.22 Which of the following is preferred for unimportant works?
A. coated metal arc welding
B. bare metal arc welding
C. tungsten electrode welding
D. inert gas welding
Ans.: B
Q.23_____ welding can be done satisfactory with D.C supply only.
A. coated electrodes
B. carbon electrodes
C. bare electrodes
D. tungsten electrodes
Ans.: C
Q.24 In ____ process, work piece to be welds are pressure together by mechanical pressure exerted through electrodes.
A. spot welding
B. arc welding
C. butt welding
D. flash arc welding
Ans.: A
Q.25 The diameter of the welding electrode is approximately give by__
A. D = t^2
B. D = t
C. D = √t
D. D = t^3
Ans.: C
[D = tip diameter in inches, t = sheet thickness in inches]
Q.26 Spot welding is generally employed for ____
A. projection welding
B. overlapping joints
C. continuous joints
D. all of the above
Ans.: B
Q.27 Applications of spot welding are__
A. manufacturing of metal sheet
B. making frame and boxes
C. welding of automobile body work, toys
D. all of the above
Ans.: D
Q.28 Which of the following is/are true of spot welding?
A. mechanical pressure is not less than 1000 lbs/sq.inch
B. current density in the body of the spot welding electrode as high as 5000 A/sq. inch
C. current density at electrode tips it may be 300000 A/ sq. inch
D. all of the above
Ans.: D
Q.29 On which of the following the success of welding operation is depends?
A. welding time
B. welding current
C. Welding pressure
D. all of the above
Ans.: D
Q.30 In welding process, greater is the welding current then ____
A. greater the welding time
B. shorter the welding time
C. welding time does not depend on welding current
D. none of the above
Ans.: B