A copper bar and a wooden bar are fixed together. A sheet of paper is wrapped closely around the junction. The bar is then heated strongly in the middle for a brief period, and the paper turns brown on only one side. Which side turns brown, and what does this indicate about wood and copper?
- Abrown side: copper; wood: conductor; copper: insulator
- Bbrown side: copper; wood: insulator; copper: conductor
- Cbrown side: wood; wood: conductor; copper: insulator
- Dbrown side: wood; wood: insulator; copper: conductor