Electric Welding MCQs

16. Helium produces which of the following?

(a) Deeper penetration
(b) Faster welding speeds
(c) Narrower heat affected zone in base metal
(d) All of the above

Answer
Answer. d

17. Due to which of the following reasons aluminium is difficult to weld?

(a) It has an oxide coating
(b) It conducts away heat very rapidly
(c) Both (a) and (b)
(d) None of the above

Answer
Answer. c

18. Welding leads have

(a) high flexibility
(b) high current handling capacity
(c) both (a) and (b)
(d) none of the above

Answer
Answer. c

19. Air craft body is

(a) spot welded
(b) gas welded
(c) seam welded
(d) riveted

Answer
Answer. d

20. For arc welding, current range is usually

(a) 10 to 15 A
(b) 30 to 40 A
(c) 50 to 100 A
(d) 100 to 350 A

Answer
Answer. d

21. Spot welding is used for

(a) thin metal sheets
(b) rough and irregular surfaces
(c) costings only
(d) thick sections

Answer
Answer. a

22. Galvanising is a process of applying a layer of

(a) aluminium
(b) lead
(c) copper
(d) zinc

Answer
Answer. d

23. A seamless pipe has

(a) steam welded joint
(b) spot welded joint
(c) arc welded joint
(d) no joint

Answer
Answer. d

24. Motor-generator set for D.C. arc welding has generator of

(a) series type
(b) shunt type
(c) differentially compound type
(d) level compound type

Answer
Answer. d

25. Plain and butt welds may be used on materials upto thickness of nearly

(a) 5 mm
(b) 10 mm
(c) 25 mm
(d) 50 mm

Answer
Answer. c

26. In argon arc welding argon is used as a

(a) flux
(b) source of heat
(c) agent for heat transfer
(d) shield to protect the work from oxidation

Answer
Answer. d

27. During arc welding as the thickness of the metal to be welded increases

(a) current should decrease, the voltage should increase
(b) current should increase, voltage remaining the same
(c) current should increase, the voltage should decrease
(d) voltage should increase, current-remaining the same

Answer
Answer. b

28. In D.C. arc welding

(a) electrode is made positive and workpiece negative
(b) electrode is made negative and workpiece positive
(c) both electrodes, as well as workpiece, are made positive
(d) both electrodes, as well as workpiece, are made negative

Answer
Answer. b

29. The purpose of coating on arc welding electrodes is to

(a) stabilise the arc
(b) provide a protecting atmosphere
(c) provide slag to protect the molten metal
(d) all of the above

Answer
Answer. d

30. 50 percent duty cycle of a welding machine means

(a) machine input is 50 percent of rated input
(b) machine efficiency is 50 percent
(c) machine works on 50 percent output
(d) machine works for 5 minutes in a duration of 10 minutes

Answer
Answer. d