**139** This was Tuesday, 4/16. The AP class was determining the relationship between the magnetic field strength and distance from a long current-carrying wire. Almost all of my photos turned out blurry. I am not sure what I had messed up in my phone’s camera settings.

# Category Archives: circuits

# Loop Rule

**127** (Tuesday, March 26th) I love this question in Chapter 27 of Halliday, Resnick, and Walker. We spent a while in class talking about which conservation of energy loop or loops you should choose to write loop equations for in order to determine the current through resistor R. There is one loop where you can solve for the unknown with one equation. If you don’t choose that loop, you will have multiple unknowns and will need multiple loops and multiple equations to answer the question. (All batteries are ideal and have emf = 4 V and all resistors are identical and have resistance = 4 Ω.)