A photodiode is made of a semiconductor with a bandgap of $1.42 \; \text{eV}.$ Given that Plank’s constant is $6.626 \times 10^{-34} \; \text{Js,}$ the speed of light in vacuum is $3 \times 10^{8} \; \text{m/s,}$ and $1 \; \text{eV} = 1.6 \times 10^{-19} \; \text{J,}$ the cut-off wavelength (in nanometers) of the photodiode is _________ (round off to one decimal place)