Conductor and insulator — পরিবাহী ও অপরিবাহী
Conductors let current flow (metals, graphite); insulators block it (rubber, glass, dry wood) because their electrons cannot move.
Definition
A conductor carries electric current easily; an insulator refuses it. Metals conduct because their electrons are free to drift through a sea of shared electrons, which is why copper wire runs through every home. In insulators such as rubber, plastic, glass or dry wood, electrons are tightly bound and cannot move. Curiosities exist: graphite conducts though it is non-metal, diamond does not though it is carbon, and pure water barely conducts — it needs dissolved ions.
For example
Electricians stand on dry wooden stools and wear rubber gloves while fixing lines, because wood and rubber are insulators; the current prefers the easy copper path.