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Question
State Kirchhoff's rules and explain on what basis they are justified.
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Solution
Kirchhoff’s first rule (Junction rule): The algebraic sum of the currents meeting at a point in an electrical circuit is always zero.
\[\sum_{} I = 0\]
This law is justified on the basis of law of conservation of charge.
Kirchhoff’s second law (Loop rule): In a closed loop, the algebraic sum of the emfs is equal to the algebraic sum of the products of the resistances and the current flowing through them.
\[\sum_{} I = 0\]
This law is justified on the basis of law of conservation of energy.
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