Q = vzniknuté teplo vo vodiči [J]
Q = U*I*t
U = I*R
Q = R*I^2*t <= Joule-Lenzov zákon

t = 75 m = 4500 s
U = 220 V
I = 2,72 A
Q = ?

R = U/I
R = 220/2,72
R = 80,82 Ω
Q = R*I^2*t
Q = 80,88*2,72^2*4500
Q = 2 692 472 J