why we count flashes n quenching of neon during the experiment of flashing and quenching to find unknown capacitance??

The neon lamp experiment used for experimentally measuring the capacitance of an unknown capacitor is based on the principle that the neon lamp glows only when the potential applied across its ends exceeds a particular value (flashing potential) and at this point, it becomes conducting. As a result of this, the capacitor begins to get discharged across the neon lamp because of which the potential difference across the lamp falls. When this potential becomes less than a particular value (quenching potential), the bulb stops glowing.

The capacitance of the unknown capacitor is measured using a formula that depends on the time taken between two flashes. The formula is of the form:  C=kt where ‘t’ is the time between two flashes, ‘k’ is a a constant value for the given arrangment, and ‘C’ is the value of the unknown capacitance.

Hence, by measuring the time taken for a fixed number of flashes to occur, we can then calculate the average time interval between two flashes. Hence, counting of the flashes is done.