Consider two resistances R₁ and R₂ are connected in series across a potential difference of V volts as shown in figure.

The total current ‘I’ divides into two parts I₁ and I₂ .I₁ flowing through the R₁ and I₂ flowing through the R₂.Then the total resistance of the circuit is,

R_eq=R₁R₂/R₁+R₂

Applied voltage is , V=I*R_eq

Voltage across resistance R₁, V₁=I₁*R₁

Voltage across resistance R₂, V₂=I₂*R₂

In parallel circuit the voltage across all the resistances is same therefore,

V = V₁ = V₂

V=I₁*R₁

I₁ = V/R₁ ----(1)

Where V=IR_eq

=I(R₁*R₂/R₁+R₂) from module 14

Substitute in eq (1)

I₁ = I(R₁*R₂/(R₁+R₂)R₂)

I₁ = I*R₂/R₁+R₂

Similarly,

I₂= I*R₁/R₁+R₂

• Current through one of the resistance = Total current* opposite resistance/sum of the product of all resistances connected in parallel