Question

Сила тока короткого замыкания источника равна 15 А. Когда зажимы источника соедирили проводником сопротивлением 5 Ом , сила тока в цепи стала равна 2 А. Чему равно внутреннее сопротивление источника?

Answer 1

Составляем систему уравнений

Доя короткооо замыкания
Iкз=Е/r
15=E/r

Для полной цепи
I=E/(R+r)
2=E/(5+r)

Е=15r
2(5+r)=15r
13r=10
r=10/13Ом Ответ

Answer 2

Ik=15 A    R=5 Ом   I=2 A   r=?
===
Ik=E/r    E=Ik*r
I=E/(R+r)=Ik*r/(R+r)
r=I*R/(Ik-I)=2*5/(15-2)=0.77 Ом
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Answer 3

Calculation of Internal Resistance of the Source

To calculate the internal resistance of the source, we can use Ohm's Law, which states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance. The formula for Ohm's Law is:

V = I * R

Where: - V is the voltage across the conductor, - I is the current flowing through the conductor, and - R is the resistance of the conductor.

In this case, we have the following information:

- Current of the short-circuit: 15 A - Current when the conductor with a resistance of 5 Ω is connected: 2 A

Let's assume that the internal resistance of the source is Ri.

When the source is short-circuited, the entire voltage of the source is dropped across the internal resistance, and the current flowing through the circuit is equal to the short-circuit current, which is 15 A.

So, we can write the equation as:

15 A = V / Ri (Equation 1)

When the conductor with a resistance of 5 Ω is connected, the voltage across the conductor can be calculated using Ohm's Law:

V = I * R (Equation 2)

Substituting the values into Equation 2, we get:

V = 2 A * 5 Ω = 10 V

Now, we can substitute the value of V into Equation 1:

15 A = 10 V / Ri

To find the value of Ri, we can rearrange the equation:

Ri = 10 V / 15 A

Calculating this expression, we find:

Ri = 0.67 Ω

Therefore, the internal resistance of the source is approximately 0.67 Ω.