If each resistor in the circuit shown is 5.0 Ω, and the battery is 12.0 V, what does the second ammeter (A2) read?
R2 and R3 are in parallel....their effective resistance is (r2 * r3)/ (r2+r3) = 25/10 = 2.5 ohms
(they each have the same current through them)
the resistance of the entire circuit is R4 + 2.5 ohms + R1 = 12.5 ohms
The current in the circuit V/R = I 12 v/ 12.5 ohms = 960 mA
R2 and R3 split this current 960/2 = 480 mA (or .48 A )