A spacecraft in low inclination LEO will undergo regular eclipsing of the Sun and this is a big issue for power management. How fast is the light-to-dark transition, say 90% to 10% sunlight intensity or something similar.
Maybe choose an orbit in the plane of the ecliptic for simple geometry, and an altitude of 500 km.
Is it milliseconds, seconds, tens of seconds? Is the transition time in LEO mostly determined by geometry or by meteorology?
When I saw eclipse duration exact to one millisecond in this answer I began to wonder just how to define when eclipse happens, and how long it takes.