a) E = P.t = 1000 . 8 . 3600 = 2´88.107 J = 2´88.107 J . 0´24 cal/J = 6´91.106 cal

b)Precio = 0´1 kW . 8 h . 0´083007 €/kW h = 0´066 €

c)
La resistencia de la estufa es
R = P/V2 = 1000/2202 = 0´021 Ω
E = V2R.t= 1252.0´021.8.3600 J = 9´45.106 J = 9´45.106 J . 0´24 cal/J = 2´27.106 cal.