1) Einstein proposed that electrons on the surface of a metal gradually absorb enery from photons until they have enough engery to elave the surface
A) True
B) False

2) Niels Bohr's model of the hyrdogen atom
A) was controversial becaue it contradicted accepted principles of physics
B) held that electrons existed in allowed orbits and nowhere else
C) accounted for the observed spectrum in hydrogen
D) all of these are true