The voltage-arc length characteristic of a DC arc is given by V=20+4L, where L is in mm. During a welding operation arc length is expected to vary between 4 and 6mm with the welding current limited between 450 and 550 amps.
(i) If the power source has a linear characteristics, the open circuit voltage is
(a) 36 V (b) 44 V (c) 72 V (d) 80 V
(ii) The arc power at an arc length of 5mm is
(a) 10 kW (b) 14 kW
(c) 20 kW (d) 80 kW