Solar power follows a bell curve of efficiency through the daylight hours. Based on the rated output of the panel, the average yield of watts generated over a period would allow only so many net hours a day total, not that the sun only shines for 5 hours, but that the energy generated equals a fixed number of watts per day. A 500 watt panel could be generating 50 watts between 7:00 am and 8:00 am, which is (roughly) equivalent to 10 minutes at the rated output.

Energy could be viewed as the accumulation of effort, and watts (power) being the rate of accumulation. You can say 500 watts for 5 hours, or 210 watts for 12 hours (or whatever elapsed time is from dusk to dawn), or anything in between, including a varying rate over time (the bell curve) but the net will still must work out to 2500 watt hours generated, or accumulated.