An electron in a mercury atom drops from energy level f to energy level c by emitting a photon having an energy of 1. 8.20eV

2. 5.52eV

3. 2.84eV

4. 2.68eV

it’s 2

Explanation: you can find the answer on the physics reference sheet

first thing first of the answer is with technology. second thing second thing is that the big bang theory did not happened u see they say it did but what they dont realize is that like dinasures are still a round they might deny it but they and look at these 12 foot human skelteons they find lets see didnt the bible say something about giants. hope this peace.