# What is the source of EMF in a chemical cell?

Now, we know that emf is induced when there is a flow of charge. Since, there is a flow of charge in the cell, battery and generator. Therefore, we can say that am emf can be induced in all the three sources. Therefore, the source of emf is **cell, battery and generator**.

## What do you mean by internal resistance of cell?

Internal resistance refers to **the opposition to the flow of current offered by the cells and batteries themselves resulting in the generation of heat**. Internal resistance is measured in Ohms. The relationship between internal resistance (r) and emf (e) of cell s given by. e = I (r + R)

## What is internal resistance and what are the factors affecting internal resistance?

Greater the conductivity of the electrolyte, lesser is the internal resistance of the cell. That is, internal resistance **depends on the nature of the electrolyte**. The internal resistance of a cell is inversely proportional to the common area of the electrodes dipping in the electrolyte.

## What factors affect internal resistance of a battery?

In practice, the internal resistance of a battery is dependent on its **size, state of charge, chemical properties, age, temperature, and the discharge current**.