GATE 2024 ME – Question 63
In an arc welding process, the voltage and current are 30 V and 200 A, respectively. The cross-sectional area of the joint is 20 mm$^2$ and the welding speed is 5 mm/s. The heat required to melt the material is 20 J/s. The percentage of heat lost to the surrounding during the welding process is _________ (*rounded off to 2 decimal places*).
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Correct answer: 99.17 to 100.17
Explanation
The heat supplied is $VI = 30 \times 200 = 6000$ J/s. The question says that the heat needed to melt the material is 20 J/s. So the heat lost is $6000 - 20 = 5980$ J/s, which is $\frac{5980}{6000} \times 100 = 99.67$ % of the supply.