A series combination of two resistors of resistance 12 Ω and 8 Ω is connected across a source of emf 24 V. What is the potential difference across 8 Ω resistors?

The Potential difference across the 8 Ω resistor = 9.6 V

Explanation:

In a series combination of resistor, The total resistance

Rt = R₁ + R₂ ... Equation 1

Where Rt = total resistance, R₁ = Resistance of the first resistor, R₂ = resistance of the second resistor.

Given: R₁ = 12Ω, R₂ = 8Ω.

Substituting these vales into equation 1

Rt = 12 + 8

Rt = 20 Ω.

Since both resistors are connected in series, The same current flows through both resistors.

from ohms law,

V = IR ... Equation 3

I = V/R ... Equation 2

where I = current flowing through both resistors, V = Emf, R = total resistance of the circuit

Also given : V = 24 V, R = 20 Ω,

Substituting these values into equation 3,

I = 24/20

I = 1.2 A.

Note: Since both resistors are connected in series, The same current flows through both resistors.

The Potential difference across the 8 Ω resistor

V = 1.2*8

V = 9.6 V

The Potential difference across the 8 Ω resistor = 9.6 V