_____ is a good conductor of electricity.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Graphite
Graphite is a form of carbon in which each carbon atom is joined to only three others, in flat layers. The fourth electron of every atom is free to move along the layers, so graphite conducts electricity well; it is the only common non-metal that does, and it is used for electrodes and the brushes of electric motors.
Why the other options are incorrect
Option (1) Wood — Incorrect. Dry wood has no free charges and is an insulator.
Option (3) Rubber — Incorrect. Rubber is a good insulator, which is why it covers electric wires and lines electricians’ gloves.
Option (4) Charcoal — Incorrect. Charcoal is amorphous carbon, without graphite’s ordered layers, and conducts electricity only poorly.