How will you conclude that the same potential difference (voltage) exists across three resistors connected in a parallel arrangement to a battery ?

Explanation

The experimental set-up comprises of three resistors `R_(1), R_(2)` and `R_(3)` which are joined in parallel combination and connecting them with a battery, an ammeter (A), a voltmeter (V) and a plug key K, as shown in figure (a).
The key K is closed and the voltmeter and ammeter readings are recorded.

The key K is open and removing the ammeter and voltmeter from the circuit and insert the voltmeter V in parallel with `R_(1)` and ammeter is series with the resistor `R_(1)`, as shown in fig. (b)

Similarly, measuring the potential differences across resistance `R_(2)` and `R_(3)`. It is found that voltmeter gives identical reading which leads to conclude that the voltage or potential difference across each resistors is same and equal to the potential difference across the combination.