Home › Previous year questions › GATE 2023 PI › Question 34GATE 2023 PI – Question 34 Manufacturing Processes I · Joining of Materials · 1 mark · Numerical answer
Resistance spot welding uses current 4500 A for 0.2 s. Effective interface resistance is 400 × 10⁻⁶ Ω and thermal efficiency is 50%. Find heat used to form the weld in J (integer).
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Show answer and explanation Correct answer: 810 to 810
Explanation Electrical heat is $I^2Rt=4500^2(400\times10^{-6})(0.2)=1620$ J. Applying efficiency gives $Q=0.5(1620)=\mathbf{810}$ J.
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