A black hole is a cosmological object that is created when a massive star comes to the end of its life and collapses under its own gravity. Black holes have massive gravitational fields that even light cannot escape beyond a certain distance. Before being engulfed, matter that is pulled into a black hole should become very hot and emit electromagnetic radiation.
Answer:
2.11eV
Explanation:
We know that speed of light is it's wavelength times frequency.
Planck's constant is 
The energy gap is calculated by multyplying the light's frequency by planck's constant:
Hence, the energy gap is 2.11eV
Answer:
The main use for gypsum is in the production of Plaster of Paris and drywall products. Gypsum is also used as a soil conditioner.
Explanation:
