일반물리학 2 — Circuits: Problem 57

57 (a) In Fig. 27-54, what current does the ammeter read if $\mathcal{E} = 5.0\text{ V}$ (ideal battery), $R_1 = 2.0\text{ }\Omega$, $R_2 = 9.0\text{ }\Omega$, and $R_3 = 6.0\text{ }\Omega$? (b) The ammeter and battery are now interchanged. Show that the ammeter reading is unchanged.