# In an electrical circuit consisting of a current source with an EMF of 6V and a conductor

**In an electrical circuit consisting of a current source with an EMF of 6V and a conductor with a resistance of 1 Ohm, a current of 2A flows. What is the impedance?**

EMF = 6 V.

R = 1 ohm.

I = 2 A.

R “-?

The total resistance of the circuit R “is the sum of the resistance of the wire R and the internal resistance of the current source r: R” = R + r.

Ohm’s law for a closed circuit states that the current in the circuit I is equal to the ratio of the electromotive force of the current source EMF to the sum of the external resistance R and the internal resistance of the current source, that is, the total resistance of the circuit: I = EMF / (R + r) = EMF / R “.

R “= EMF / I.

R “= 6 V / 2 A = 3 ohms.

The internal resistance of the current source r will be: r = R “- R = 3 Ohm – 1 Ohm = 2 Ohm.

Answer: The total resistance of the circuit is R “= 3 ohms.