In the circuit shown in Fig. E26.18, ε = 36.0 V, R₁= 4.00 Ω, R₂= 6.00 Ω, and R₃= 3.00 Ω.

(a) What is the potential difference V_ab between points a and b when the switch S is open and when S is closed?

(b) For each resistor, calculate the current through the resistor with S open and with S closed. For each resistor, does the current increase or decrease when S is closed?

Figure E26.18

R1 R3 R2