You are riding in a train, gazing into the distance through its window. As close objects streak by, you notice that the nearby fluorescent lights make dashed streaks. Explain.
When riding in a train and looking outside through the window pane, the fluorescent light makes dashed streaks.
Stroboscopic effects is a kind of illusion, when the light falls on a moving objects (in this case our eyes), they appears to be running slowly in either both directions. The alternating current fluctuates between a negative to positive magnitude crossing zero many times per second.
For example as in India the alternating current is supplied with a frequency of 50 Hz , this means the lamp dims and brightens repeatedly 50 times in a second.
Hence, it is due to the stroboscopic effect, the fluorescent light makes a dashed streak.