Q1. Choose the below option in terms of ascending order of band gap energyAnswer: 2. Graphite, Silicon, Diamond Diamond has the highest bandgap energy, about 6eV. It is this high bandgap which separates the filled valance band from the conduction band and makes Diamond an insulator. Though Graphite is also a form of Carbon, like Diamond, its crystal symmetry is different and band gap energy is about 1eV, making it a conductor.