Explain it detail about emf of a cell.

hi

The electromotive force emf, is the maximum potential difference between two electrodes of a galvanic or voltaic cell. This quantity is related to the tendency for an element, a compound or an ion to acquire (i.e. gain) or release (loss) electrons.

In physics, emf refers to voltage generated by a battery or by the magnetic force according to Faradays laws, which states that a time varying magnetic field will induce an electric current.

It is important to note that the electromotive force is not a force in the classical physics sense—as can be seen in the fact that it is measured in volts and not newtons.

Formally, emf is the external work expended per unit of charge to produce an electric potential difference across two open-circuited terminals.The electric potential difference produced is created by separating positive and negative charges, thereby generating an electric field.The created electrical potential difference drives current flow if a circuit is attached to the source of emf. When current flows, however, the voltage across the terminals of the source of emf is no longer the open-circuit value, due to voltage drops inside the device due to its internal resistance.