GATE 2026 PI – Question 13
A 6 kW arc-welding source joins two similar metals. Total energy loss is 50%, weld cross-sectional area is 10 mm² and specific melting energy is 15 J/mm³. Find welding speed (mm/s).
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Correct answer: (B) 20
Explanation
Useful power is $6000(1-0.50)=3000$ J/s. Welding at speed v melts $10v$ mm³/s and needs $15(10v)=150v$ J/s. Therefore $v=3000/150=20$ mm/s: **B**.