Two cells each of emf E and internal resistance r are connected in such a way that their positive terminals are connected to point X and negative terminals are connected to point Y. The potential difference between X and Y is

zero

The correct answer is Option (1) → zero

Two cells connected with positive terminals together and negative terminals together are in **opposing series** configuration.

Effective emf: $E_\text{net} = E - E = 0$

Internal resistance in series: $r_\text{total} = r + r = 2r$

Potential difference between X and Y:

$V_{XY} = E_\text{net} = 0 \, \text{V}$

$V_{XY} = 0 \, \text{V}$