# In a series electrical circuit, the resistances of the conductors are 2 ohms and 4 ohms.

**In a series electrical circuit, the resistances of the conductors are 2 ohms and 4 ohms. The voltmeter shows a voltage of 12 V. What is the voltage on the first conductor if the second is 8 V?**

When the conductors are connected in series, their total resistance is equal to their sum.

Rtot = R + R1

With a series connection, the current flowing through the elements is the same:

I = I1 = I2

The voltage at the ends is equal to the sum of the stresses on the elements:

U = U1 + U2

Let’s find the strength of the current that flows in the second resistance:

According to Ohm’s law, the amount of current is directly proportional to the applied voltage and inversely proportional to its resistance:

I = U / R

I2 = U2 / R2 = 8/4 = 2 A

Find U1:

U1 = I1 * R1 = 2 * 2 = 4V

Let’s check:

U = U1 + U2

12 = 8 + 4

It all fits together.

Answer: the voltage on the first element is 4 V.