WELDING MCQ SET 1
Q1. Welding is a process of:
A) Joining two materials using adhesive
B) Joining two materials by heating them
C) Cutting the materials
D) Polishing metal surfaces
Answer: B) Joining two materials by heating them
Explanation: Welding joins two or more materials (usually metals) by applying heat, pressure, or both to create a permanent bond.
Q2. The most common type of welding used in fabrication shops is:
A) Gas welding
B) Arc welding
C) TIG welding
D) MIG welding
Answer: B) Arc welding
Explanation: Arc welding is widely used due to its simplicity, low cost, and ability to weld most metals.
Q3. In arc welding, the heat is produced by:
A) Gas flame
B) Chemical reaction
C) Electric arc
D) Friction
Answer: C) Electric arc
Explanation: An electric arc between the electrode and workpiece generates intense heat for melting the metal.
Q4. The temperature of an electric arc in welding is approximately:
A) 1000ยฐC
B) 2500ยฐC
C) 4000ยฐC
D) 6000ยฐC
Answer: D) 6000ยฐC
Explanation: The arc temperature in arc welding can reach up to 6000ยฐC, enough to melt most metals.
Q5. Which of the following is not a welding process?
A) MIG welding
B) TIG welding
C) Brazing
D) Gas cutting
Answer: D) Gas cutting
Explanation: Gas cutting is a material removal process, not a joining process like welding.
Q6. The main purpose of flux in welding is:
A) To remove dirt
B) To prevent oxidation
C) To increase temperature
D) To polish weld
Answer: B) To prevent oxidation
Explanation: Flux cleans the metal surface and prevents oxidation by forming a protective slag layer.
Q7. The coating on a welding electrode is called:
A) Shield
B) Flux coating
C) Filler
D) Electrode paste
Answer: B) Flux coating
Explanation: The flux coating stabilizes the arc and protects the molten metal from atmospheric contamination.
Q8. In gas welding, the fuel gas commonly used is:
A) Methane
B) Propane
C) Acetylene
D) Hydrogen
Answer: C) Acetylene
Explanation: Oxy-acetylene welding is common because acetylene burns at a very high temperature (~3200ยฐC).
Q9. The chemical formula of acetylene gas is:
A) CโHโ
B) CHโ
C) CโHโ
D) CโHโ
Answer: A) CโHโ
Explanation: Acetylene is represented by CโHโ, containing two carbon and two hydrogen atoms.
Q10. In oxy-acetylene welding, the oxygen and acetylene are mixed in:
A) Oxygen cylinder
B) Welding torch
C) Regulator
D) Hose pipe
Answer: B) Welding torch
Explanation: The gases mix in the torch nozzle before combustion.
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