Question

ДАЮ 100 БАЛЛОВ СРОЧНО ПОМОГИТЕ!! Площади поперечных сечений медных проволок с одинаковыми длинами равны 0,05 мм2 и 2 мм2. Какая из них обладает меньшим сопротивлением; во сколько раз? (показать решение задачи) ​

Answer 1

Ответ:

меньш сопрот у второй проволоки в 40 раз

Объяснение:

R1= ρℓ/s1= ρℓ/0,05
R2= ρℓ/s2= ρℓ/2
R1/R2= ρℓ/0,05:ρℓ/2=2/0,05=40 (раз)

Answer 2

Calculation of Resistance for Copper Wires

To determine which of the two copper wires with different cross-sectional areas has a smaller resistance, we need to calculate the resistance for each wire. The resistance of a wire can be calculated using the formula:

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

Where: - Resistivity (ρ) is a material property of copper, which is constant. - Length (L) is the length of the wire. - Cross-sectional Area (A) is the area of the wire's cross-section.

Let's calculate the resistance for each wire and compare the results.

Calculation for the Wire with a Cross-Sectional Area of 0.05 mm²

Let's assume the length of the wire is 1 meter.

Using the formula, we can calculate the resistance:

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

The resistivity of copper is a constant value, which is approximately 1.68 x 10^-8 Ω·m.

Substituting the values into the formula:

Resistance (R) = (1.68 x 10^-8 Ω·m) x (1 m) / (0.05 x 10^-6 m²)

Simplifying the expression:

Resistance (R) = 33.6 Ω

Calculation for the Wire with a Cross-Sectional Area of 2 mm²

Using the same length of 1 meter, we can calculate the resistance for the wire with a cross-sectional area of 2 mm².

Substituting the values into the formula:

Resistance (R) = (1.68 x 10^-8 Ω·m) x (1 m) / (2 x 10^-6 m²)

Simplifying the expression:

Resistance (R) = 8.4 Ω

Comparison of Resistances

Comparing the calculated resistances, we find that the wire with a cross-sectional area of 0.05 mm² has a resistance of 33.6 Ω, while the wire with a cross-sectional area of 2 mm² has a resistance of 8.4 Ω.

Therefore, the wire with a cross-sectional area of 2 mm² has a smaller resistance compared to the wire with a cross-sectional area of 0.05 mm².

To determine the ratio between the resistances, we can divide the resistance of the wire with a larger cross-sectional area by the resistance of the wire with a smaller cross-sectional area:

Resistance Ratio = Resistance (2 mm²) / Resistance (0.05 mm²)

Resistance Ratio = 8.4 Ω / 33.6 Ω

Resistance Ratio = 0.25

Therefore, the wire with a cross-sectional area of 2 mm² has a resistance that is 0.25 times the resistance of the wire with a cross-sectional area of 0.05 mm².

I hope this helps! Let me know if you have any further questions.