## PHYS208 Fundamentals of Physics II

### Hint for Ch. 28, 14E

The tank and indcator resistances are in series.

### Hint for Ch. 28, 33E

There are 8 possible combinations! Ignoring the trivial case where all switches are open (no current), there are three settings with one switch closed, three different circuits with two switches closed, and yet a different circuit when all three switches are closed.

Even though this exercise involves a lot of drawing and algebraic manipulation, if you are able to complete all seven circuits satisfactorally, then you may feel confident that you understand how to deal with combinations of series and parallel resistors.

### Hint for Ch. 28, 38E

Please see my detailed series/paralled circuit example.

### Hint for Ch. 28, 55P

R2 and R3 are in parallel, assuming a "perfect" ammeter of 0 ohm resistance. This parallel combination is then in series with R1 so that the circuit reduces to a simple equivalent circuit from which the current through the emf (and R1) may be calculated. Finally, establish the voltage across the parallel combination and from that deduce the current through the ammeter (and R3).

"http://www.physics.udel.edu/~watson/phys208/exercises/hints/0220.html"
Last updated Feb. 18, 1998.
Copyright George Watson, Univ. of Delaware, 1997.