Resistance spot welding is performed on two plates of 1.5 mm thickness with 6 mm diameter electrode, using 15000A current for a time duration of 0.25sec. assuming the interface resistance to be 0.0001W, the heat generated to form the weld is
(a) 5625 W-sec(b) 8437 W-sec
(c) 22500 W-sec (d) 33750 W-sec