In copper, the valence band and conduction band overlap, allowing electrons to flow freely and making copper an excellent conductor. In contrast, in materials like silicon and germanium, there is a gap between the valence and conduction bands, making them semiconductors.
The circuit shown in the figure contains two ideal diodes \( D_1 \) and \( D_2 \). If a cell of emf 3V and negligible internal resistance is connected as shown, then the current through \( 70 \, \Omega \) resistance (in amperes) is: 