1. The problem statement, all variables and given/known data A circuit consists of three identical lamps connected to a battery. Battery has some internal resistance. Switch S, open at first, is closed. 1) What happens to brightness of lamps B and C? 2) What happens to current in battery? 3) What happens to potential across lamps A and C? 4) What happens to total power delivered to lamps by battery? See attached figure. 2. Relevant equations I = emf/R+r P = I*deltaV 3. The attempt at a solution This is my attempt at the solution; I am almost certain that my answers are correct but I would appreciate if someone could verify, and explain if possible, if I am incorrect. 1) B brightness remains the same. C brightness increases since the circuit is complete. 2) Current in battery decreases because of increased resistance. 3) Potential is unchanged for lamp A but increases for C because circuit is now closed. 4) Total power increases, since there is an increase in potential due to the closed circuit. I would appreciate any assistance, thank you!