Do You Know ?

Question:
Why do the shadow of a Tubelight is not sharp as filament bulbs ?


Answer:
The reason is simple Filament Bulb is a point source which emits the light in all direction

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and as the light travels along the straight line path , if obstructed by an object it will cause shadow . the light that diffuse into the shadowed region is very small in this case.

But the tubelight is a line source and if shadow is created by the light from one point then there is a chance that it my be diffused by the light from some other point of the same source and hence the shadows are not sharp as in the case of filament lamp.