🔄 Loop Rule

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⭐ The sum of potential changes in a closed loop is always zero.

✅$$\sum V = 0$$

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💡 Reason

✏️ Electric field is a conservative field.

In a conservative field, the work done (W) in moving a charge around a closed loop is zero.

Therefore,

$$W = 0$$

$$\frac{W}{q} = 0$$

$$V = 0$$

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🎯 Conclusion

✅ Since the electric field is conservative, the net work done around a closed path is zero.

✅ Hence, the algebraic sum of all potential rises and potential drops in a closed loop is zero.$$\sum V = 0$$

💡 This statement is known as Kirchhoff’s Loop Rule or Kirchhoff’s Voltage Law (KVL). 🔄⚡

⚡ How to Calculate Potential Changes?

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1️⃣ Resistance

🔌 Given

• Resistance: R = 3 Ω
• Current: I = 2 A

📌 Rule

➡️ Along the direction of current, potential is negative (−ve).

➡️ Opposite to the direction of current, potential is positive (+ve).

✏️ Potential Difference

From A to B (Along Current)

$$V_{AB} = -2 \times 3 = -6V$$

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From B to A (Opposite Current)

$$V_{BA} = +2 \times 3 = +6V$$

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2️⃣ Battery

🔋 Given

• Battery Voltage: 5V

📌 Rule

⚠️ Direction of current is not important.

✏️ Potential Difference

From A to B

$$V_{AB} = -5V$$

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From B to A

$$V_{BA} = +5V$$

🎯 Summary

🔌 Across a Resistance

➡️ Along current$$V = -IR$$

➡️ Opposite to current$$V = +IR$$

🔋 Across a Battery

➡️ From (+) terminal to (−) terminal$$V = -E$$

➡️ From (−) terminal to (+) terminal$$V = +E$$

💡 These sign conventions are used while applying Kirchhoff’s Loop Rule (KVL). 🔄