Circuit path analysis with switches

Steps:

• S1 closed allows current from battery to parallel branches containing L1-S2 and L2-L3.
• S2 open blocks the branch with L1, preventing current flow through L1.
• Current flows only through the L2-L3 branch in series.
• L2 and L3 receive voltage and light up; L1 remains off.

Why C is correct:

• Parallel branches follow Kirchhoff's current law: open switch isolates one path, directing all current to the active branch.

Why the others are wrong:

• A: Ignores L2-L3 path, which remains open to current.
• B: Includes L1, but S2 open blocks its branch.
• D: Includes L1, but its path is interrupted by open S2.

Final answer: C