Question

Для измерения э.д.с. своего аккумулятора автомобилист собрал замкнутую цепь, в которой последовательно соединил аккумулятор, источник тока с э.д.с. 2 В и амперметр. При этом амперметр показал ток 1 А. При изменении полярности включения аккумулятора ток в цепи изменил направление и стал равным 0,75 А. Определить в СИ э.д.с. аккумулятора.

Answer 1

Пусть ЭДС аккумулятора равен X B.
Запишем закон Ома для полной цепи:
I₁ = (ЭДСакк + ЭДСит) / R  
1 = (Х + 2) / R                                      (1)
(здесь R - сопротивление аккумулятора, источника тока и амперметра).

 При смене полярности:
0,75 = (X-2) / R                                    (2)

Разделим (1) на (2)
1/0,75 = (X+2) / (X-2)

(X-2)*1 = (X+2)*0,75
X - 2 = 0,75*X + 1,5
0,25*X = 3,5
X = 3,5 / 0,25 = 14 В

Ответ: ЭДС аккумулятора 14 вольт.

Answer 2

Calculation of the EMF of the Battery

To determine the electromotive force (EMF) of the battery, we can use the information provided in the question. The circuit consists of a battery, a current source with an EMF of 2 V, and an ammeter. When the battery is connected in the circuit, the ammeter shows a current of 1 A. When the polarity of the battery is reversed, the current in the circuit changes direction and becomes 0.75 A.

We can use the equation for the EMF of a battery in a closed circuit:

EMF = I * R

where EMF is the electromotive force, I is the current, and R is the total resistance in the circuit.

In this case, the total resistance in the circuit remains the same when the polarity of the battery is reversed. Therefore, we can equate the two equations for the EMF:

EMF1 = I1 * R

EMF2 = I2 * R

where EMF1 is the EMF of the battery when the current is 1 A, EMF2 is the EMF of the battery when the current is 0.75 A, I1 is the current of 1 A, I2 is the current of 0.75 A, and R is the total resistance in the circuit.

By rearranging the equations, we can solve for the EMF of the battery:

EMF1 / I1 = R

EMF2 / I2 = R

Since the total resistance is the same in both cases, we can equate the two equations:

EMF1 / I1 = EMF2 / I2

Substituting the given values:

2 V / 1 A = EMF2 / 0.75 A

Simplifying the equation:

**2 V * 0.