State and explain Kirchhoff's laws in electricity.

Explanation

Kirchhoff.s first law or Junction rule : It states that the algebraic sum of all currents meeting at a point is zero. i.e. `sum I = 0`.
Sign conventions
Current entering a point is taken as positive.
Current leaving the point is taken as negative.
Now applying Kirchhoff.s first law to the given figure
`I_1 + I_2 + I_3 + (-I_4) + (-I_5) = 0` or `I_1 + I_2+I_3 = I_4 + I_5`
i.e., Sum of incoming currents = Sum of outgoing currents
This law is based on law of conservation of charge.
Kirchhoff.s second law or loop law : It states that the algebraic sum of product of current and respective resistance in a closed circuit is equal to algebraic sum of e.m.f.s of cells in the circuit i.e. `sum IR = sum E`
e.m.f.: i) The e.m.f of the cell is taken as +ve if the - ve pole of the cell comes first while traversing the loop and vice versa.
IR: The product of IR is taken as +ve if the direction of current is in the same sense and it is taken as - ve if the direction of current is opposite to the sense as one moves in a closed path.