GATE 2022 MT – Question 59
Steel plates are autogenously GTA welded with arc efficiency 0.65. The first weld uses 200 A, 18 V, and speed 0.002 m/s. The second uses speed 0.0022 m/s at the same voltage. For identical heat input per weld length, its current is ______ A (nearest integer).
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Correct answer: 220 to 220
Explanation
Heat per unit weld length is $\eta VI/v$. With equal heat input, efficiency, and voltage, current is proportional to speed.
Thus $I_2=200(0.0022/0.002)=\boxed{220}$ A.