Answer 6_7_4

Power is 200 000 V x 0.025 A = 5000 W

99% is heat.  

Therefore heating effect is 4950 Js

Anode has a mass of 1 kg.

Temperature change = 4950 J s^-1 ÷ (300 J kg^-1K^-1 x 1 kg) = 16.5 K s^-1

Temperature rise to melting point = 3000 K - 300 K = 2700 K

Time taken to get to melting point = 2700 K ÷ 16.5 K s^-1 = 164 s

The anode will have melted.  Whoops!

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