Question

Який заряд проходить за 1 годину через поперечний переріз залізної дротини завдовжки 1 км з площеюпернрізу 0,5 мм квадратних, якщо напруга між їїкінцями 5 В? Питомий опір заліза 1,2×10-7 Ом×м

Answer 1

T=1 год=3600 с
L=1 км=1000 м
S=0,5 мм²=0,0000005 м²
U=5 В
p=0,00000012 Ом*м

q=?

$q=It$  
Согласно закону Ома:
$I= \frac{U}{R}$ 
Формула сопротивления:
$R= \frac{pL}{S}$ 
$I= \frac{US}{pL}$ = 5 В * 0,0000005 / 0,00000012 Ом * м / 1000 м = 0,02083 А.
Тогда заряд равен:
q=0,02083 А * 3600 с ≈ 75 Кл.

Відповідь: за 1 годину через поперечний переріз проходить заряд 75 Кл.

Answer 2

To calculate the current passing through a cross-sectional area of iron wire, 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 is the specific resistance (ρ) multiplied by the length (L) divided by the cross-sectional area (A).

Let's calculate the current passing through the iron wire:

Given: - Length of the wire (L) = 1 km = 1000 m - Cross-sectional area of the wire (A) = 0.5 mm^2 = 0.5 × 10^-6 m^2 - Voltage (V) = 5 V - Specific resistance of iron (ρ) = 1.2 × 10^-7 Ω·m

Calculating the resistance:

The resistance (R) can be calculated using the formula: R = ρ × (L / A)

Substituting the given values: R = (1.2 × 10^-7 Ω·m) × (1000 m / 0.5 × 10^-6 m^2)

Calculating the resistance: R = 2.4 × 10^-1 Ω

Calculating the current:

Using Ohm's Law: I = V / R

Substituting the given values: I = 5 V / 2.4 × 10^-1 Ω

Calculating the current: I ≈ 20.83 A

Therefore, approximately 20.83 Amperes of current will pass through the cross-sectional area of the 1 km long iron wire with a cross-sectional area of 0.5 mm^2, when a voltage of 5 V is applied across its ends.

Please note that the above calculation assumes that the wire is a perfect conductor and there are no other factors affecting the current flow.