Question

A housefly walking across a clean surface can accumulate a significant positive or negative charge. In one experiment, the largest positive charge observed was +73 pCpC. A typical housefly has a mass of 12 mgmg.How many electrons does it lose to the surface it is walking across?

Answer 1

Answer:

$4.56*10^8 \text{ electrons.}$

Explanation:

Since the fly accumulated a positive charge of +73pC, it must have lost an equal number of negative charge of -73pC to the surface (because the housefly was neutral to begin with).

Therefore, to answer our question we have to ask ourselves how many electrons combine to make -73pC of charge?

The answer is since one electron carries a charge of $-1.6*10^{-19}C$, the number $n$ of electrons that make up -73pC $(-73*10^{-12}C)$ are

$n= \dfrac{-73*10^{-12}C}{-1.6*10^{-19}C/e}$

$\boxed{n= 4.56*10^8e.}$

Thus, the housefly lost about 456 million electrons to the surface!