Odpowiedzi

2009-12-01T13:42:25+01:00
Dane
η=80%
t=20s
Wu=1100J=1100Ws
U=220V
I=?
η=Wu*100%/Wc
Wc=Wu*100%/η=1100Ws*100%/80%=1375Ws
Wc=U*I*t
I=Wc/(U*t)=1375Ws/(220V*20s)=0,31A
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2009-12-01T13:43:37+01:00
W= UIt
I= W/Ut

I=1100/220x20s= 0,25A

0,25A= 80%
x= 100%
x=0,3125A
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