Answer
When the resistors are in parallel, the potential difference across each resistor and across the equivalent resistance are all equal.
Work Step by Step
Let $\Delta V$ be the potential difference across the battery.
When the resistors are in parallel, the potential difference across each resistor is $\Delta V$. The potential difference across the parallel arrangement is $\Delta V$
When the resistors are in parallel, the potential difference across each resistor and across the equivalent resistance are all equal.
