The beads are not affected by visible light— they are chemically developed to only react to UV light and will remain white indoors or when shielded from UV light. The electromagnetic radiation needed to affect a change in the color of the beads is between 360 and 300 nm in.
Silicon dominates solar panel manufacturing because it hits a rare sweet spot: it absorbs sunlight at nearly the ideal wavelength range, it's the second most abundant element in the Earth's crust, and decades of semiconductor manufacturing have made it cheap to produce at scale.
Solar panels are predominantly oriented towards the south due to several critical reasons: 1. Maximizing sunlight absorption, 2. Adapting to technological design.
The PV panels must be mounted on a structure to maintain their position. Ground-mounted systems take up additional real estate and require an additional structure.
When a panel is placed at the right amount of tilt, direct rays falling on the surface of the panel hit more directly. So, more sunlight is absorbed in the process.