Question

Calculate the current in a series circuit if the voltage is 12.0 V and there are two resistors in series, one with a 2.00 ohm resistance, and one with a 4.00 ohm resistance.

Answer 1

The total resistance of two resistors in series is sum of their individual resistances:

$$R = R1+R2$$

where $R1 = 2\Omega$, and $R2 = 4\Omega$. Thus:

$$R = 2\Omega+4\Omega = 6\Omega$$

According to the Ohm's law, the current in a circuit with voltage $U = 12V$ and resistance $R = 6\Omega$ is:

$$I = \dfrac{U}{R} = \dfrac{12V}{6\Omega} = 2A$$

Answer. 2A.