018

De spanning U is:

a   10 v
b     8 v
c     6 v
d     5 v

UR1 = 2 V
UR2 = 2 V    >>>  UR12=UR3 = 4 V

Rt12 = R1 + R2 = 2 KΩ

Rv123 = 1/(1/R3 + 1/Rt12)

Rv123 = 1/(1K + 1/2K) = 666 Ω

I123 = U123 / Rv123 = 4 / 666 = 6mA

RT1234 = RV123 + R4 = 666 + 1K = 1K666 Ω

Ut =  I * Rt = 6mA * 1K666 = 10 v

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U=I*R

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