Which of the follow transitions would emit visible light with the highest energy? a) n=4 to n=3
b)n=4 to n=2
c) n=3 to n=2
d) n=3 to n=1
e) n=2 to n=1

since electrons are negative the answer is neagtaive

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.