The potential difference between the terminals of a battery in an open circuit is 2.2 V. When it is connected across a resistance of 5.0 Ω, the potential falls to 1.8 V. What is the internal resistance of the battery?

Explanation

To find the internal resistance of the battery, we can use the formulas:1. The emf, E, is the open-circuit voltage: E = 2.2 V.2. When the battery is connected to a resistance of 5.0 Ω, the terminal voltage V = 1.8 V.Using Ohm's Law, V = IR, where I is the current flowing through the external resistance. Therefore, I = V/R = 1.8 V / 5.0 Ω = 0.36 A.The internal resistance, r, can be found using the formula E = V + Ir, so 2.2 V = 1.8 V + 0.36 A * r.Solving for r gives r = (2.2 V - 1.8 V) / 0.36 A = 1.11 Ω.The correct answer is 1.11 Ω.Other Options:Option A (9.11 Ω), Option B (2.11 Ω), Option C (3.11 Ω), and Option E (0.11 Ω) are incorrect as they result from miscalculations or misunderstandings of the relationship between emf, internal resistance, and external resistance.