Parallel Cells Maintain Single-Cell e.m.f.

Steps:

• e.m.f. is the potential difference a cell provides, measured in volts (J/C).
• In parallel connection, identical cells share the same voltage across terminals.
• The battery's e.m.f. equals the individual cell's e.m.f., as voltages add in parallel branches.
• For three identical cells, the total e.m.f. is unchanged from one cell.

Why B is correct:

• Parallel combination preserves e.m.f. per Kirchhoff's voltage law, equaling one cell's value in J/C.

Why the others are wrong:

• A: e.m.f. sums only in series, not parallel.
• C: N/V is not the unit for e.m.f.; summing applies to series.
• D: N/V is incorrect unit for e.m.f.

Final answer: B