# Power Calculations

**1. The problem statement, all variables and given/known data**

Concider the circuit shown below. Find the current i

_{R}flowing through the resitor. Find the power for each element in the circuit. Which elements are absorbing power?

**2. Relevant equations**

Ohm’s law: U = IR;

Kirchhoff’s Current Law and Kirchhof’s Voltage Law.

**3. The attempt at a solution**

My instructor told me that the resistor is supplying power and the voltage is absorbing power. But I just didn’t get it.

By the diagram, the current i_{R} flows in a clockwise direction. With KCL, i_{R} = 2A, and with Ohm’s law, v_{R} = i_{R}R = 10V. But How can I know whether the resistor is absorbing power or supplying power? Because I can’t determine the polarity between the resitor with KVL.

It’s clear that the voltage source is absorbing power, and if it were a battery, it would be charging.

But I can’t understand how can a resistor SUPPLY power to other elements in the circuit as my instructor told me.

http://ift.tt/NMV8wm

## Leave a comment