What is inside the electric cell which helps in giving current to the bulb ?

A dry cell consists of a metal container in which a low moisture electrolyte paste covers the graphite rod or a metal electrode. Generally, the metal container will be zinc whose base acts as a negative electrode (anode) and a carbon road acts as a positive electrode (cathode). It is surrounded by manganese dioxide and low moisture electrolyte like ammonium chloride paste, which will produce a maximum of 1.5V of voltage, and they are not reversible.

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The half cell reaction process has the following steps

Step 1:

During the process, a reduction reaction occurs within the moisturized electrolyte, which comprises manganese dioxide (MnO2) and ammonium chloride (NH4Cl) and graphite serves as solid support for the reduction reaction

2NH4+ + 2MnO2 →Mn2O3 + 2NH3 + H2O

Step 2:

Zinc container serves as an anode and undergoes an oxidation reaction

Zn → Zn2+ + 2e-

Zinc-carbon cell is the most common dry cell and is also called Leclanche cell. The alkaline battery has almost same half-cell reaction, where KOH or NaOH replaces the ammonium chloride and half-cell reactions are

ZNCl2 + 2NH3 → Zn(NH3)2Cl2

2MnO2 + H2 → Mn2O3 + H2O

The overall reaction is,

Zn + 2MnO2 + 2NH4Cl → Mn2O3 + Zn(NH3)2Cl2 + H2O