Question

имеется трехжильный провод, каждая жила, которого состоит из 20 тонких медных проводков. Диаметр каждого по 0,8 мм. Определите сопротивление этого провода, если его длина 100 метров. ​

Answer 1

Ответ:0,17 Ом

Объяснение:

R=ρ*L/S=4*ρ*L/πd²*n

R= 4*0,017 Ом*м/мм²* 100м / 3,14* 0,64 мм²* 20=6,8 Ом/ 40=0,17 Ом

Answer 2

Calculating the Resistance of the Wire

To calculate the resistance of the wire, we can use the formula:

Resistance (R) = Resistivity (ρ) x Length (L) / Cross-sectional Area (A)

Where: - Resistivity (ρ) is a characteristic of the material the wire is made of. - Length (L) is the length of the wire. - Cross-sectional Area (A) is the area of the wire's cross-section.

The resistivity of copper is approximately 1.68 x 10^-8 ohm-meter.

The cross-sectional area of the wire can be calculated using the formula for the area of a circle:

A = πr^2

Where: - r is the radius of the wire, which is half the diameter.

Given: - The wire has 20 thin copper strands, each with a diameter of 0.8 mm.

Let's calculate the resistance of the wire using these values.

Calculation

First, we need to find the total cross-sectional area of the wire. Since there are 20 strands, we can multiply the cross-sectional area of one strand by 20 to get the total cross-sectional area.

The radius of each strand is half of the diameter, so the radius (r) of each strand is 0.8 mm / 2 = 0.4 mm = 0.0004 m.

The total cross-sectional area (A) of the wire is: A = 20 * π * (0.0004)^2

Now, we can calculate the resistance using the formula: R = ρ * L / A

Given: - Length (L) = 100 meters - Resistivity (ρ) = 1.68 x 10^-8 ohm-meter

Substitute the values into the formula to find the resistance.

Result

After performing the calculations, the resistance of the wire is found to be approximately 0.021 ohms.