Question

2. проводник сделанный из алюминия имеет длину 2 км и площадь поперечного сечения 0,2 мм² (удельное сопротивление алюминия равно 2,8 × 10 ‐⁸ Ом × м) проводник включен в цепь постоянного(?) тока напряжением 40 В. найдите силу тока.​

Answer 1

Ответ:

≈0.14 A

Объяснение:

L=2*10³ м     S=0.2*10⁻⁶ м²     ρ=2.8*10⁻⁸ Ом*м     U=40 B     I=?

===

R=ρ*L/S=2.8*10⁻⁸*2*10³/(0.2*10⁻⁶)=280 Ом

I=U/R=40/280≈0.14 A

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Answer 2

Calculation of Current

To find the current flowing through the aluminum conductor, 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, the resistance of the aluminum conductor can be calculated using the formula:

R = (ρ × L) / A

Where: - R is the resistance of the conductor - ρ (rho) is the resistivity of aluminum (given as 2.8 × 10⁻⁸ Ω × m) - L is the length of the conductor (given as 2 km, which is equal to 2000 m) - A is the cross-sectional area of the conductor (given as 0.2 mm², which is equal to 0.2 × 10⁻⁶ m²)

Let's calculate the resistance first:

R = (2.8 × 10⁻⁸ Ω × m × 2000 m) / (0.2 × 10⁻⁶ m²)

Calculating this expression gives us the resistance of the aluminum conductor.

Calculation Steps

1. Convert the cross-sectional area from mm² to m²: - 0.2 mm² = 0.2 × 10⁻⁶ m²

2. Substitute the given values into the formula: - R = (2.8 × 10⁻⁸ Ω × m × 2000 m) / (0.2 × 10⁻⁶ m²)

3. Simplify the expression: - R = (2.8 × 10⁻⁸ Ω × m × 2000 m) / (0.2 × 10⁻⁶ m²) - R = (2.8 × 10⁻⁸ × 2000) / (0.2 × 10⁻⁶) - R = (2.8 × 2000) / 0.2

4. Calculate the resistance: - R = 5600 / 0.2 - R = 28000 Ω

Now that we have the resistance of the aluminum conductor, we can calculate the current using Ohm's Law.

Calculation of Current

Ohm's Law states that:

I = V / R

Where: - I is the current - V is the voltage (given as 40 V) - R is the resistance of the aluminum conductor (calculated as 28000 Ω)

Let's calculate the current flowing through the aluminum conductor:

I = 40 V / 28000 Ω

Calculating this expression gives us the current flowing through the aluminum conductor.

Calculation Steps

1. Substitute the given values into the formula: - I = 40 V / 28000 Ω

2. Simplify the expression: - I = 40 / 28000

3. Calculate the current: - I ≈ 0.00143 A (rounded to 5 decimal places)

Therefore, the current flowing through the aluminum conductor is approximately 0.00143 A.