250+ TOP MCQs on Resistance Welding-1 and Answers

Manufacturing Engineering Multiple Choice Questions on “Resistance Welding-1”.

1. Which of the following is not true about fusion welding?
a) It depends upon the characteristics of heat source.
b) It depends upon the nature of deposition of the filler material
c) It does not depend upon the heat flow characteristics in the joint
d) It depends upon the gas metal or slag metal reaction
Answer: c
Clarification: Fusion welding depends upon the heat flow characteristics in the joint. The quantity of heat required to melt a given volume of metal depends on: (1) The heat to raise the temperature of the solid metal to its melting point, (2) The melting point of the metal, (3) The heat to transform the metal from solid to liquid phase at the melting point.

2. Which of the following is not used to produce heat during welding?
a) Electric arc
b) Chemical flame
c) Electrical resistance
d) Acetone flame
Answer: d
Clarification: For welding heating, different kinds of energy are converted into heat, typically, electrical, beam, chemical and mechanical energy and also their combinations.

3. In which of the following welding process heat and pressure is applied on the joint but no filler material or flux is added?
a) Arc welding
b) Resistance welding
c) Gas welding
d) Thermite welding
Answer: b
Clarification: Resistance welding is the method to joint two plain metal work pieces together by running an electrical current through them. No filler metal and no flux are needed in this type.

4. Total resistance in welding is composed of:
(i) Resistance of electrode
(ii) Contact resistance between electrode and work piece
(iii) Contact resistance between two work piece plates
(iv) Resistance of work piece
Which of the following is correct?
a) i
b) ii, iii and iv
c) ii and iv
d) I, ii, iii and iv
Answer: d
Clarification: Total resistance is the equivalent resistance of all resistances present in the welding circuit during the process of welding.

5. If 20 amperes of current is flowing in a wire for 1 minute of time having a resistance of 1000 ohm. Then the amount of heat generated in resistance welding will be (in kilo joules)?
a) 24000
b) 240000
c) 24000000
d) 2400
Answer: a
Clarification: Heat produced = I²RT, where ‘I’ is the current, ‘R’ is resistance and ‘T’ is the time in seconds. For the given problem, heat produced = (20²)×(1000)×(1×60)
Therefore heat produced = 400 × 1000 × 60 = 24,000 KJ.

6. Which of the following is true about electrodes?
a) Low electrical conductivity and low mechanical strength
b) Low electrical conductivity and high mechanical strength
c) High electrical conductivity and low mechanical strength
d) High electrical conductivity and high mechanical strength
Answer: d
Clarification: To get maximum efficiency, electrodes should have high electrical conductivity and high mechanical strength.

7. Which of the following is true about resistance welding?
a) Electrodes of higher resistivity is used for lower resistive piece
b) Electrodes of higher resistivity is used for higher resistive piece
c) Electrodes of lower resistivity is used for lower resistive piece
d) Electrodes of lower resistivity is used for higher resistive piece
Answer: a
Clarification: To get high efficiency, electrodes of higher resistivity is used for lower resistive piece.

8. According to the joules law?
a) The poor conductor heats up to a higher degree than a good conductor
b) The poor conductor heats up to a lower degree than a good conductor
c) The poor conductor heats up to equal degree than a good conductor
d) Joules law does not relate to heat
Answer: a
Clarification: Joules law relate power with voltage and current as: Power (P) = Voltage (V) × Current (I). It conveys that poor conductor heats up to a higher degree than a good conductor.

9. Which of the following electrode has very high electrical conductivity but low strength?
a) Copper chromium alloys
b) Copper cobalt alloys
c) Copper beryllium alloys
d) Copper cadmium alloys
Answer: d
Clarification: Copper cadmium alloys have very high electrical conductivity but low strength. They produce very less heat during the current flow.

10. Which of the following electrode has low electrical conductivity but high strength?
a) Copper chromium alloys
b) Copper cobalt alloys
c) Copper beryllium alloys
d) Copper cadmium alloys
Answer: a
Clarification: Copper chromium alloys electrode has low electrical conductivity but higher strength. They generate more heat during the current flow.