Question

The soft light of sun spreads over the sky before the sunrise is called

Answer 1

Heya...

The Soft Light of sun spreading over the sky before the sunrise is called TWILIGHT.

Answer 2

The soft light of sun spreads over the sky before the sunrise is called Twilight 

When sun remains beyond the horizon (but not too far from it) the light does not comes directly to our eyes, so we can't see sun. But since light comes to atmosphere with very small angle to horizontal the scattered light from the dusts of the atmosphere comes to the surface of the earth. That's why we see light after sunset and before sunrise . 
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