Kirchhoff law – problems and solutions

1. If R₁ = ۲ Ω، ر₂ = ۲ Ω، ر₃ = 6 Ω, determine the بریښنا جریان flows in the circuit below.

پیژندل شوی:

رژیم ۱ (ر₁) = ۴ Ω

مقاومت کوونکی ۳ (R₂) = ۴ Ω

مقاومت کوونکی ۳ (R₃) = ۲ اوه

Source of emf 1 (E₁) = 9 V

Source of emf 2 (E₂) = 3 V

SE busca: د برېښنا جریان (I)

حل:

This question relates to د Kirchhoff قانون. How to solve this problem:

لومړی, choose the direction of the current. You can decide the opposite current or direction in the clockwise direction.

دوهم, when the current through the resistor (R) there is a potential decrease so that V = IR signed negative. دریم, if the current moves from low to high voltage (- to +) then the source of emf (E) signed positive because of the charging of energy at the emf source. If the current moves from high to low voltage (+ to -) then the source of emf (E) signed negative because of the emptying of energy at the emf source.

In this solution, the direction of the current is the same as the direction of clockwise rotation.

- IR₁ + ای₁ - IR₂ - IR₃ - ای₂ = 0

– 2 I + 9 – 4 I – 6 I – 3 = 0

– ۵۰۰ I + ۱۲ = ۰

– ۵۰۰ زه = – ۱۲

I = -6 / -12

زه = 0.5

The electric current flows in the circuit are 0.5 A. The electric current signed positive means that the direction of the electric current is the same as the direction of clockwise rotation. If the electric current is negative, then the electric current is opposite the clockwise direction.

2. Determine the electric current that flows in the circuit as shown in the figure below.

حل:

In this solution, the direction of the current is the same as the direction of clockwise rotation.

-20 – 5I -5I – 12 – 10I = 0

-۳ – ۹I = ۰

-۳ = ۹I

زه = -۸ / ۴

I = -1.6 A

Because the electric current is negative, the direction of the electric current is actually opposite to the clockwise direction. The direction of electric current is not the same as estimation.

3. Determine the electric current that flows in the circuit as shown in the figure below.

حل:

In this solution, the direction of current is the same as the direction of clockwise rotation.

– I – 6I + 12 – 2I + 12 = 0

-9I + 24 = 0

-9I = -24

زه = 24 / 9

I = 8 / 3 A

4. An electric circuit consists of four resistors, R₁ = 12 Ohm, R₂ = 12 Ohm, R₃ = 3 Ohm and R₄ = 6 Ohm, are connected with source of emf E₁ = 6 Volt, E₂ = 12 Volt. Determine the electric current flows in the circuit as shown in figure below.

پیژندل شوی:

مقاومت کوونکی ۳ (R₁) = ۴ Ω

مقاومت کوونکی ۳ (R₂) = ۴ Ω

مقاومت کوونکی ۳ (R₃) = ۲ اوه

مقاومت کوونکی ۳ (R₄) = ۲ اوه

Source of emf 1 (E₁) = ۲۲۰ ولټه

Source of emf 2 (E₂) = ۲۲۰ ولټه

غوښتل شوي: The electric current flows in the circuit (I)

حل:

مقاومت کوونکی ۱ (R₁) and resistor 2 (R₂) are connected in parallel. The equivalent resistor :

1 / R₁₂ = 1/R₁ + 1/R₂ = ۱/۳ + ۱/۳ = ۲/۳

R₁₂ = ۱۲/۵ = ۲.۴ اوهم

In this solution, the direction of current is the same as the direction of clockwise rotation.

- IR₁₂ - ای₁ - IR₃ - I R₄ + ای₂ = 0

– 6 I – 6 – 3I – 6I + 12 = 0

– 6I – 3I – 6I = 6 -12

– 15I = – 6

I = -6/-15

I = 2/5 A

5. Determine the electric current that flows in circuit as shown in figure below.

پیژندل شوی:

مقاومت کوونکی ۳ (R₁) = ۴ Ω

مقاومت کوونکی ۳ (R₂) = ۴ Ω

مقاومت کوونکی ۳ (R₃) = ۲ اوه

مقاومت کوونکی ۳ (R₄) = ۲ اوه

Source of emf 1 (E₁) = ۲۲۰ ولټه

Source of emf 2 (E₂) = ۲۲۰ ولټه

غوښتل شوي: The electric current that flows in circuit

حل:

مقاومت کوونکی ۱ (R₃) and resistor 4 (R₄) are connected in parallel. The equivalent resistor :

1 / R₃₄ = 1/R₃ + 1/R₄ = ۱/۶ + ۱/۳ = ۱/۶ + ۲/۶ = ۳/۶

R₃₄ = ۱۲/۵ = ۲.۴ اوهم

In this solution, the direction of current is the same as the direction of clockwise rotation.

- IR₁ - IR₂ - E₁ - IR₃₄ + ای₂ = 0

– 10I – 6I - 8 - 4I + 12 = 0

– 10I – 6I - 4I = 8:12 - XNUMX:XNUMX

- 20I = – 4

I = -4/-20

I = 1/5 A

زه = 0.2 الف

6. Determine the electric current that flows in circuit as shown in figure below.

پیژندل شوی:

مقاومت کوونکی ۳ (R₁) = ۴ Ω

مقاومت کوونکی ۳ (R₂) = ۴ Ω

مقاومت کوونکی ۳ (R₃) = ۲ اوه

مقاومت کوونکی ۳ (R₄) = ۲ اوه

Source of emf 1 (E₁) = ۲۲۰ ولټه

Source of emf 2 (E₂) = ۲۲۰ ولټه

غوښتل شوي: The electric current that flows in circuit

حل:

مقاومت کوونکی ۱ (R₁) and resistor 2 (R₂) are connected in parallel. The equivalent resistor :

1 / R₁₂ = 1/R₁ + 1/R₂ = ۱/۶ + ۱/۳ = ۱/۶ + ۲/۶ = ۳/۶

R₁₂ = 6/7 Ω

The direction of current is the same as the direction of clockwise rotation.

E₁ - زه R₁₂ - ای₂ - زه R₄ - IR₃ = 0

12 – (6/7)I – 6 – 4I – 6I = 0

12 – 6 – (6/7)I – 4I – 6I = 0

6 – (6/7)I – 10I = 0

6 = (6/7)I + 10I

6 = (6/7)I + (70/7)I

6 = (76/7)I

(6)(7) = 76I

۸ = ۸ زه

زه = ۸/۸

زه = 0.5 الف