Why in the metre bridge experiment it is necessary to take readings for direct and reverse current?

In a Wheatstone bridge circuit if the connections of the battery and galvanometer are interchanged, does it affect the results of observation in any way?

What happens when we get the balance point in a potentiometer experiment?

Why we get the exact emf of a cell when it is measured by the potentiometer method.

We are to find a very accurate value of a potential difference. Which type of potentiometer and driving cell should we chose?

How voltmeter and ammeter should be joined in an electric circuit?