Question

Какую опору имеет отрезок медной проволоки диаметром d =1 мм, если ее масса m=0,893 кг. Удельная oпоpа меди ρ = 1,75·10 -8 Ом·м, плотность меди D = 8,93·103 кг/м3 . Какая концентрация электронов проводимости, если на каждый ион меди в кристалле приходится один электрон проводимости? Молярная масса меди – 63,546 г/моль.

Answer 1

Ответ:

Сопротивление равно= уд. сопрот. *(длина/площадь)

Длина = объём/площадь

Площадь = (пи*диаметр в квадрате) /4

Объем = масса/плотность

В итоге:

Сопротивление = уд. сопрот. *((16*масса) /пи в квадрате* диаметр в четвертой * плотность)

Answer 2

Calculation of Resistance:

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

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

Given: - Diameter of the wire (d) = 1 mm - Mass of the wire (m) = 0.893 kg - Specific resistivity of copper (ρ) = 1.75 x 10^-8 Ω·m - Density of copper (D) = 8.93 x 10^3 kg/m^3

First, we need to find the length (L) and cross-sectional area (A) of the wire.

The volume of the wire can be calculated using the formula:

Volume (V) = Mass (m) / Density (D)

The length of the wire can be calculated using the formula:

Length (L) = Volume (V) / Cross-sectional Area (A)

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

Cross-sectional Area (A) = π x (d/2)^2

Let's calculate the values step by step:

1. Calculate the volume of the wire: - Volume (V) = 0.893 kg / (8.93 x 10^3 kg/m^3) - Volume (V) = 0.0001 m^3

2. Calculate the cross-sectional area of the wire: - Cross-sectional Area (A) = π x (1 mm / 2)^2 - Cross-sectional Area (A) = 0.000785 m^2

3. Calculate the length of the wire: - Length (L) = 0.0001 m^3 / 0.000785 m^2 - Length (L) = 0.127 m

4. Calculate the resistance of the wire: - Resistance (R) = (1.75 x 10^-8 Ω·m) x (0.127 m) / 0.000785 m^2 - Resistance (R) = 2.84 x 10^-6 Ω

Therefore, the resistance of the copper wire with a diameter of 1 mm is approximately 2.84 x 10^-6 Ω.

Calculation of Electron Concentration:

To calculate the electron concentration in the copper crystal, we can use Avogadro's number and the molar mass of copper.

The number of moles (n) of copper in the wire can be calculated using the formula:

Number of moles (n) = Mass (m) / Molar mass (M)

The number of copper ions in the crystal is equal to the number of moles (n) of copper.

The number of electrons (N) can be calculated by multiplying the number of copper ions by the number of electrons per ion.

The electron concentration (C) can be calculated by dividing the number of electrons (N) by the volume (V) of the crystal.

Let's calculate the values step by step:

1. Calculate the number of moles of copper: - Number of moles (n) = 0.893 kg / (63.546 g/mol) - Number of moles (n) = 0.0141 mol

2. Calculate the number of copper ions: - Number of copper ions = 0.0141 mol

3. Calculate the number of electrons: - Number of electrons = Number of copper ions

4. Calculate the electron concentration: - Electron concentration (C) = Number of electrons / Volume (V) - Electron concentration (C) = Number of electrons / (0.0001 m^3)

Therefore, the electron concentration in the copper crystal is equal to the number of copper ions, which is approximately 0.0141 mol.

Please note that the electron concentration is given in moles, not in a specific unit.