Odpowiedź:
t = 3 h = 3*3600s = 10 800 s
I = 5 A
U = 230 V
cena = 80 gr/kWh
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W = ?
Koszt = ?
P = U*I = 230V*5A = 1150 W = 1,15 kW
W = P*t
W = 1150W*10800s = 12 420 000 J = 12,42 MJ (megadżuli)
W = 1,15 kW*3h = 3,45 kWh
Koszt = W*cena = 3,45kWh * 80gr/kWh = 276 gr = 2 zł 76 gr