Voltage - Kirchoff laws

At a voltage of 2.5V, a current I1= 20mA flows through the resistor. What will the voltage be at the resistor's ends when the current I2= 1,2A passes through it?

Correct answer:

U₂ =  150 V

Step-by-step explanation:

$$\begin{gathered} U_1=2.5\text{V} \\ {I}_1=20\text{mA}\to \text{A}=20:1000\text{A}=0.02\text{A} \\ {I}_2=1.2\text{A} \\ I=U/R \\ R=U_1/I_1=2.5/0.02=125\Omega \\ {U}_2=R\cdot I_2=125\cdot 1.2=150=150\text{V} \\ \text{ Verifying Solution: } \\ {U}_3=U_1\cdot \frac{I_2}{I_1}=2.5\cdot \frac{1.2}{0.02}=150\text{V} \\ {U}_3=U_2 \end{gathered}$$

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