Which property measures the amount of charge flowing through a circuit

Describe how the fermi level changes with donor level, temperature and contact with p and n type semiconductors

Light traveling in a medium with a refractive index 1.19 is incident on a plate of another medium with index of refraction 1.79. at what angle of incidence is the reflected light fully polarized?

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.