Two steel sheet of 1 mm thick are resistance welded in a lap joint wi...
Calculation of Heat Generated in Welding
- The heat generated in welding can be calculated using the formula Q = I^2Rt, where Q is the heat generated, I is the current, R is the effective resistance, and t is the time.
- Substituting the given values, we get Q = (10000 A)^2 x 100 x 10^-6 Ω x 0.1 sec = 100 J.
Calculation of Volume of Joint
- The volume of the joint can be calculated using the formula V = πr^2h, where r is the radius and h is the height.
- Substituting the given values, we get V = π(2.5 mm)^2 x 1.5 mm = 29.3215 mm^3.
Calculation of Heat Required to Melt Steel
- The heat required to melt steel can be calculated using the formula Qm = ρVΔHf, where ρ is the density of steel, V is the volume, and ΔHf is the heat of fusion.
- Substituting the given values, we get Qm = 0.00786 g/mm^3 x 29.3215 mm^3 x 10 J/mm^3 = 2.298 J.
Calculation of Heat Lost to Surroundings
- The heat lost to surroundings can be calculated using the formula Qlost = Q - Qm, where Q is the heat generated and Qm is the heat required to melt steel.
- Substituting the calculated values, we get Qlost = 100 J - 2.298 J = 97.702 J.
- Therefore, the heat lost to surroundings is 97.702 J, which is closest to option A (705.476 J).