When a current drawn from a battery is 0.5 A, its terminal potential difference is 20 V. And when current drawn from it is 2.0 A , the terminal voltage reduces to 16 V . Find out e.m.f and internal resistance of the battery.

Explanation

To solve the problem, we will use the relationship between the electromotive force (e.m.f.), terminal voltage, current, and internal resistance of the battery. The formula we will use is:

\[ V = E - i \cdot r \]

Where:
- \( V \) is the terminal voltage,
- \( E \) is the e.m.f. of the battery,
- \( i \) is the current drawn from the battery,
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