Say I am sitting in the shadow, but the sunlight gets reflected by some window pane onto me. Does this contain enough UV light to give me a sunburn?
You can get a burn from a reflection. There’s a building in Las Vegas that caused this problem due to its windows and angle towards the sun.
There are too many variables to say if you’ll get a burn though.
Such as how much light is reflected, whether any windows have UV coating, how much exposure you get, and how susceptible you are to burning.
But it’s possible.
In the right conditions; you can melt vehicles with just windows/glass panes.
Let’s assume the reflection is coming from just one flat glass pane.
According to this Stack Exchange answer, glass reflects around 4-100% of the UV in sunlight depending on the angle of incidence. So you could probably get a sunburn if the angle is low enough (like if the Sun is almost directly overhead and reflecting off a vertical window).
It really depends on the type of glass some glass transmits UV light and some types reflect UV light. And that is not taking into account the pile of other factors that will affect it.
Yes. You burn more easily near the water due to reflected light.