1. The problem statement, all variables and given/known data 5 lamps are connected in series (one after the other in a circle) across the terminals of an energy source. Each lamp has a voltage drop across its terminals that is double the value of the one to the left of it. Which lamp will glow the brightest? 2. Relevant equations V = I x R 3. The attempt at a solution I know how to apply Ohm's law to components of a circuit, and to the whole circuit. I understand that the current through all lamps is the same, and that they have different resistances and voltage drops across them, and I can calculate all that fine. It's just the brightness - I do not understand what makes a lamp brighter or dimmer.. Is it the voltage drop across the lamp that determines it brightness? Or is it the current? Thanks for any assistance!