What is potentiometer?Draw a circuit diagram of a metre bridge used to determine the unknown resistance  of a given wire.

What does the term 'end error' in a metre bridge circuit metre and how is it corrected ? How will be balancing point be affected, if the positions of the battery and galvanometer are inter- changed in a metre bridge experiment ? Give reason for your answer.

Obtain the condition under which the current flowing, in the 'current detecting device', used in the circuit shown in the figure, becomes zero.