Question

State Kirchhoff’s Loop law and explain.

Answer 1

Loop law : 

The algebraic sum of the increases and decreases in potential difference across various components of the circuit in a closed circuit loop must be zero. 

Explanation : 

Let us imagine in a circuit loop the potential difference between the two points at the beginning of the loop has a certain value. As we move around the circuit loop and measures the potential difference across each component in the loop, the potential difference may decrease or increase depending upon the nature of the element like a resistor or battery. But when we have completely traversed the circuit loop and arrive back at starting point. The net change in the potential difference must be zero. Thus the algebraic sum of changes in potential difference is to be zero. 

(OR) 

Let us apply loop law to a circuit as below.

for the loop ACDBA – V₂ + I₂R2₂ – I₁R₁ + V₁ = 0 

for the loop EFDCE -(I₁ + I₂ )R₃ – I₂ R₂ + V₂ = 0

for the loop EFBAE -(I₁ + I₂ )R₃ – I₁ R₁ + V₁ = 0