# Two conductors of the same length and of the same material are connected in series. The diameter of the first conductor is 1 mm

**Two conductors of the same length and of the same material are connected in series. The diameter of the first conductor is 1 mm, the second is 2 mm. The system has a voltage of 300 V. Determine the voltage on the second conductor.**

Given:

d1 = 1 mm;

d2 = 2 mm;

L1 = L2;

U = 300 B.

Find: U2.

Decision:

In order to find the radius, we will use this formula. It must be found, since it is a mandatory variable in the formula for finding the voltage.

Let’s write the formula:

R1 = пo * L / S1 = 4 * пo * L / (n * d1 ^ 2)

The situation is similar with the second radius.

R2 = пo * L / S2 = 4 * пo * L / (n * d2 ^ 2).

From this we get:

R1 / R2 = d2 ^ 2 / d1 ^ 2 = 4.

Next, we find the current strength:

I = U1 / R1 = U2 / R2.

Let’s make a proportion

U1 / U2 = R1 / R2 = 4

U1 = U-U2

Let’s find the voltage.

U2 = U / 5 = 300/5 = 60 V

Answer: 60