Question

Визначити силу струму на ділянці кола, яка складається з константанового дроту довжиною 20 м і перерізом 1,26 мм², якщо напруга на кінцях цієї ділянки 40 В.​

Answer 1

Ответ: 5,1А

Объяснение:

Дано:

l=20м

S=1,26мм²

ρ=0,5 Ом*мм²/м

U=40В

------------------------

I-?

I=U/R

R=ρl/S=0,5*20/1,26=7,9 Ом

I=40/7,9=5,1А

Answer 2

To determine the current flowing through a section of a circuit, we can use Ohm's Law, which states that the current (I) is equal to the voltage (V) divided by the resistance (R). In this case, we need to find the resistance of the section of the circuit.

The resistance of a wire can be calculated using the formula:

R = (ρ * L) / A

Where: - R is the resistance of the wire - ρ (rho) is the resistivity of the material (constantan in this case) - L is the length of the wire - A is the cross-sectional area of the wire

Let's calculate the resistance first:

Given: - Length of the wire (L) = 20 m - Cross-sectional area of the wire (A) = 1.26 mm² = 1.26 * 10^(-6) m² - Resistivity of constantan (ρ) = *0.49 x 10^(-6) Ωm* [[1]]

Using the formula, we can calculate the resistance (R):

R = (ρ * L) / A

R = (0.49 x 10^(-6) Ωm * 20 m) / (1.26 x 10^(-6) m²)

Calculating the above expression, we get:

R ≈ 0.78 Ω

Now that we have the resistance, we can use Ohm's Law to find the current (I):

Given: - Voltage across the section of the circuit (V) = 40 V

Using Ohm's Law:

I = V / R

I = 40 V / 0.78 Ω

Calculating the above expression, we get:

I ≈ 51.28 A

Therefore, the current flowing through the section of the circuit is approximately 51.28 Amperes.

Please note that the above calculations assume that the wire is an ideal conductor and there are no other resistive elements in the circuit.