Two 1 mm thick steel sheets are to be spot welded at a current of 5000 A. Assuming effective resistance to be 200 μm and current flow time of 0.2 second, heat generated during the process will be
A. 0.2 Joule
B. 1 Joule
C. 5 Joule
D. 1000 Joule
Answer: Option D
This Question Belongs to Mechanical Engineering >> Manufacturing And Production Technology
Formula : (I^2) R ∆t
= (5000)^2 × (200×10^-6) × 0.2
= 25×10^6. × 200×10^-6 × 0.2
= 5000×0.2
=1000J
H=I^2Rt
=5000^2*200x10^-6*0.2
=1000
How ??