What shape is the unit cell of ruby?

The electronic structure or chlorine is 2.8.7 what is the electronic structure of fluorine?

An electron is traveling with initial kinetic energy k in a uniform electric field. the electron comes to rest momentarily after traveling a distance d. (a) what is the magnitude of the electric field

How to tell if two objects are in thermal equilibrium 1.the objects have the same temperature 2.the objects are the same size 3.the objects are touching each other 4.the objects temperatures are changing