--schakelaar open--

P2 = P1 = 25 Watt     want R₁=R₂

Pt = 2x25 = 50 Watt

P = UxI  >>>  
I = P / U = 50/100 = 0.5 A

U =  I x R  >>> 
Rt = U  / I = 100 /0.5 =200 Ohm
 
R₁ = 100 Ohm en R₂ = 100 Ohm

Ur = Ir x R     0.5x100= 50 V

---schakelaar gesloten---

R₁ vervalt , wordt kortgesloten

I = U / R 100/100 = 1 A

P = U x I 100x1 = 100 Watt

Ur₂ = IR₂   x R₂ = 1x100 =100 V

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