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

Explanation

Suppose 3 resistances are `R_(1), R_(2)` and `R_(3)`. We will connect these resistances in parallel with an ammeter (A), a voltmeter (V), a plug key (K)and a battery of known voltage as shown in figure given below. We will close the key K and record the ammeter and voltmeter readings.

Now, we will open the key and switch the position of voltmeter and ammeter as show in the figure given below.

We will close the switch and note the readings. Similarly, we will switch the position of voltmeter to resistances `R_(2)` and `R_(3)` and observe the readings. We will find that readings of ammeter keeps on changing but readings of voltmeter in all cases almost remain same in all cases.