# Electric input power

Solve problems related to electric power:

a) U = 120 V, I = 0.5 A, P =?
b) P = 200 W, U = 230 V, I =?
c) I = 5 A, P = 2200W, U =?

Result

P1 =  60 W
I2 =  0.87 A
U3 =  440 V

#### Solution:

$U_{1}=120 \ \text{V} \ \\ I_{1}=0.5 \ \text{A} \ \\ \ \\ P_{1}=U_{1} \cdot \ I_{1}=120 \cdot \ 0.5=60 \ \text{W}$
$P_{2}=200 \ \text{W} \ \\ U_{2}=230 \ \text{V} \ \\ \ \\ I_{2}=P_{2} / U_{2}=200 / 230 \doteq \dfrac{ 20 }{ 23 } \doteq 0.8696 \doteq 0.87 \ \text{A}$
$I_{3}=5 \ \text{A} \ \\ P_{3}=2200 \ \text{W} \ \\ \ \\ U_{3}=P_{3}/I_{3}=2200/5=440 \ \text{V}$

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