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2009-12-11T19:02:35+01:00
Tp=12 C
Tk=100 C
/\T=88C
U=220V
t=14min=860s
R=44 Ohm
Cw= 4200J/kg*C

R=U/I
I=U/R
I=220V/44 Ohm
I=5 A

W=U*I*t
W=220V*5A*860s
W=946000J

m=Q/Cw*/\T
m=946000J/4200J*88
m=2.55kg
2 3 2
2009-12-12T00:50:19+01:00
R = 44 Ω
U = 220V
t = 14min = 840s
Tp = 12° C
Tk = 100° C
ΔT = Tk - Tp
ΔT = 100° - 12° C 88°C
Cw = 4200J/kg*C

R = U / I
I = U / R
I = 220V / 44Ω
I = 5 A

W = P * t = U * I * t
W = 220V * 5A * 840s
W = 944000J = 944kJ

W = Q = cw * m * ΔT
m = Q / (Cw*ΔT)
m = 944000J / (4200J/kg*° * 88°C)
m = 2,55kg
2 3 2