Question

State the law of combination of resistances in parallel.

Answer 1

In a parallel combination, the voltage remains the same across each resistor but the current gets divided. Let I_1, I₂ and I₃ be the current across resistors R_1, R₂ and R₃, respectively. 

`l=l_1+l_2+l_3` 

`V=LR,V=L_1R_1,L_2R_2, V=L_3R_3` 

`I=v/R,I_1 V/R_1, I_2=V/R_2,L_3 V/R_1`  

Using thrsr value, We get: 

`V/R=V/R_1+V/R_2+V/R^1` 

`1/R=1/R_1+1/R_2+1/R_1`

So, the total resistance is the sum of the reciprocal of the individual resistances.