KIRCHHOFF’S SECOND LAW
Kirchhoff’s second law is also known as VOLTAGE LAW (OR) LOOP LAW
This law is based on LAW OF CONSERVATION OF ENERGY.
Kirchhoff’s second law states that ” THE ALGEBRAIC SUM OF ALL THE POTENTIAL DIFFERENCES ALONG A CLOSED LOOP IS ZERO”.
CONVENTIONS:
- Take any direction as the direction of traversal.(Either clockwise or anticlockise)
- EMF of the cell is POSITIVE if the direction of the traversal is from its NEGATIVE terminal to POSITIVE terminal. (NPP)
- EMF of the cell is NEGATIVE if the direction of the traversal is from its POSITIVE terminal to NEGATIVE terminal. (PNN)
- The IR product is taken as POSITIVE if the resistor is traversed in the same direction as the assumed current.
EXAMPLE :
Find the current in each wire using Kirchhoff’s voltage law (the second law)
MODIFIED CIRCUIT:
SOLUTION:
The modified circuit is shown above. All elements are connected in series.Here we can select the direction of traversal as anti-clockwise.In a series combination of the circuit,the current through all the components is the same.Consider the current through each element be I . Now we can apply Kirchhoff’s second law.
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