Consider a zener diode with the breakdown voltage 6.2V.Write any one application of zener diode

Consider a zener diode with the breakdown voltage 6.2V.What is the significance of the breakdown volt age for a zener diode?

Consider a zener diode with the breakdown voltage 6.2V.How is zener diode different from an ordinary diode?

What is reverse osmosis? Write any one of its applications.