Odpowiedź:
W = 135 J
I = 4,2 A
U = 2,8 V
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t ?
P = U*I = 2,8V*4,2A = 11,76 W
W = P*t
t = W/P = 135J/11,76W ≈ 11,48 s
t = 11,48 s
lub
W = Q*U
Q = I*t
W = Q*I = I*t*U
t = W/(U*I) = 135J/(2,8V*4,2A) = 135J/11,76W = 11,48 s
t = 11,48 s