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Respected teacher, Galvanometer is used to detect the direction of electric current.Then why is voltmeter used in electrochemical cell or Galvanic cell?

Galvanometer is an instrument that detects and measures electric currents.

An electrochemical cell, two electroder are placed separately and connected by an external wire.

In one part of the cell, oxidation and the other part reduction take place.

The electrons lost in the oxidation reaction travel through the external circuit to the reduction reaction, where they reduce the oxidising agent.

The parts of the electrochemical cell are called half cells. The energy is given out as electrical energy.

Batteries have both a positive and negative terminal, the potential difference between the positive and negative terminal is measured in volts.

A high resistance voltmeter is used to measure the potential difference between the electrodes of the cell. It is high resistance, so that negligible current flows, and therefore maximum potential difference is being measured.