A cell of e.m.f. ε and internal resistance r sends a current of 1.0 A when it is connected to an external resistance of 1.9 ` Omega `. But it sends a current of 0.5 A when it is connected to an resistance of `3.9 Omega ` calculate the values of ` epsi` and r .

Explanation

To solve the problem, we need to apply Ohm's Law and the concept of internal resistance in a circuit. Let's break down the solution step by step.

### Step 1: Understand the Circuit
We have a cell with an electromotive force (e.m.f.) denoted as \( E \) and an internal resistance denoted as \( r \). The cell is connected to an external resistor \( R \).

### Step 2: Set Up the Equations
We are given two scenarios:
1. When the external resistance \( R_1 = 1.9 \, \Omega \), the current \( I_1 = 1.0 \, A \).
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