When 6.00 Volts Becomes 5.866 Volts - The Distance Between Theory and Reality

The students had gone back to class.

The laboratory was quiet.

Years ago, out of curiosity, I connected four ordinary 1.5 V dry cells using whatever I could find nearby. A few wires, a battery holder and some rather messy connections.

The calculation was easy:

1.5 V × 4 = 6.00 V

But the multimeter had other ideas.

It displayed:

5.866 V

Not 6.00 V.

Not the textbook answer.

Just reality.

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Why?

In KSSM Physics, the e.m.f. (electromotive force) is the energy supplied by a source to move one coulomb of charge around a complete circuit. It represents the battery's ideal voltage.

Real batteries, however, are never ideal.

Internal resistance, ageing cells and imperfect connections all reduce the voltage we actually measure.

That is why:

Terminal Voltage ≤ e.m.f.

AHA! Textbooks predicted 6.00 V. Reality gave 5.866 V. Physics lives in the space between expectation and observation. Not by memorisation, but by CURIOSITY. 

P/S: A spontaneous experiment from years ago. Today, I share it with my readers.