60 Important Electrical Welding MCQ Question and Answer | PDF Free Download
1.For arc welding, current range is usually
- A10 to 15 A
- B30 to 40 A
- C50 to 100 A
- D100 to 350 A
2.Spot welding is used for
- AThin metal sheets
- BRough and irregular surface
- CCosting only
- DThick sections
3.Galvanizing is a process of applying a layer of
- AAluminium
- BLead
- CCopper
- DZinc
4.A seamless pipe has
- ASteam welded joint
- BSpot welded joint
- CArc welded joint
- DNo joint
5.Motor-generator set for DC Arc welding has generator of
- ASeries type
- BShunt type
- CDifferentially compound type
- DLevel compound type
6.Plain and butt welding may be used on materials up to thickness of nearly
- A5 mm
- B10 mm
- C25 mm
- D50 mm
7.In argon arc welding, argon is used as a
- AFlux
- BSource of heat
- CAgent for heat transfer
- DShield to protect the work from oxidation
8.During arc welding, as the thickness of the metal to be welded increases
- ACurrent should decrease, voltage should increase
- BCurrent should increase, voltage remaining the same
- CCurrent should increase, voltage should decrease
- DVoltage should increase, Current remaining the same
9.In DC arc welding
- AElectrode is made positive and work piece negative
- BElectrode is made negative and work piece positive
- CBoth Electrode as well as work piece are made positive
- DBoth Electrode as well as work piece are made negative
10.The purpose of coating on arc welding electrodes is to
- AStabilize the arc
- BProvide a protecting atmosphere
- CProvide slag to protect the molten metal
- DAll of the above
11.50 percent duty cycle of a welding machine means
- AMachine input is 50 percent of rated input
- BMachine efficiency is 50 percent
- CMachine works on 50 percent output
- DMachine works for 5 minutes in a duration of 10 minutes
12.During carbon arc welding, if electrode is connected to positive
- AArc will be dull
- BArc will not strike
- CMetal will not melt
- DCarbon will have tendency to go into the weld joint
13.In which of the following method of welding the molten metal is poured for joining the metals?
- AThermit welding
- BGas welding
- CTIG welding
- DArc welding
14.The electrode in atomic hydrogen welding is made of
- ACarbon
- BGraphite
- CTungsten
- DTungsten
15.The porosity of welded joint may be caused by
- ALow welding current
- BIncorrect size of electrode
- CPoor base metal
- DAny of the above
16.In electrical resistance welding the greatest resistance is offered by which of the following?
- AMetal surface
- BContact point of electrode with metal top
- CContact point of electrode with metal bottom
- DContact layer of metals to be welded
17.The tips of the electrodes, for spot welding, are made of
- ACopper alloy or pure copper
- BPorcelain
- CMica
- DCarbon
18.During spot welding the current flows for
- AFraction of a minute to several minutes
- BFraction of a seconds to several seconds
- CFew milliseconds
- DFew microseconds
19.Which of the following is not a type of resistance welding?
- AProjection welding
- BSeam welding
- CFlush welding
- DCarbon arc welding
20.The power factor of a spot welding machine is expected to be around
- AUnity
- B0.8 lagging
- C0.3 to 0.5 lagging
- D0.8 leading