Question

When you touch a friend after walking across a rug on a dry day, you typically draw a spark of about 1.89 mm. Calculate the potential difference between you and your friend just before the spark.

Answer 1

To solve this problem we will apply the concepts related to the magnitude of the electric field. Defined as the proportion of the electric potential per unit of distance, that is,

$E = \frac{V}{d}$

Where E is the magnitude of the electric field between the plates, V is the potential difference between the plates, and d is the separation of the plates

The breakdown field of air is $3.0*10^6$ N/C.

Replacing we have that the Potential is

$V = Ed$

$V = (3.0*10^6)(1.89*10^{-3})$

$V = 5670V$

Therefore the potential difference between you and your friend just before the spark is 5670V