A high resistance voltmeter measures the potential difference across a battery to be 9-0 V. On connecting a 24 2 resistor across the terminals of the battery, the voltmeter reads 7.2 V. Calculate the internal resistance of the battery.

Explanation

To solve the problem of finding the internal resistance of the battery, we can follow these steps:

### Step 1: Write down the given values
- **E** (emf of the battery) = 9.0 V
- **V** (terminal voltage when the resistor is connected) = 7.2 V
- **R** (external resistance) = 24.2 Ω

### Step 2: Use the formula relating emf, terminal voltage, internal resistance, and current
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