A battery of voltage 12 V sends a current of 400 mA to an appliance. After a long continuous use, the current drops to 320 mA and the appliance does not operate. Find :
the internal resistance of the battery.

Explanation

To find the internal resistance of the battery, we can follow these steps:

### Step 1: Identify the given values
- Initial voltage of the battery (V1) = 12 V
- Initial current (I1) = 400 mA = 0.4 A
- Current after a long use (I2) = 320 mA = 0.32 A

### Step 2: Calculate the initial resistance of the appliance
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