3. A semiconductor materials with bandgap energy of 3.39 eV are exposed to light. The electrons are being excited from valence band to conduction band. Femtosecond laser experiment estimates that the shelf-life of this electron stay in conduction band is ~8 ns before it return back to the valence band. (a) Find the wavelength that emitted by this semiconductor. (10 marks) (b) Find the fractional energy uncertainty (E/E) (10 marks) (c) Find the wavelength uncertainty (/ ) of this photon.