Question

Which charge could not be found on an object?

(1) -0.8 x 10-19 C (3) +1.6 x 10-19 C

(2) -1.6 x 10-17 C (4) +3.2 x 10-17 C

Proof: Explain your reasoning/show calculations.

Answer 1

The elementary charge (the quanta of charge) equals $e=1.6\times 10^{-19}\:\rm C.$

Hence, total charge of an object

$$q=Ne,$$

here $N$ is integer.

Let's check:

(1)

$$N=\frac{0.8\times 10^{-19}}{1.6\times 10^{-19}}=1/2 \; (\rm impossible)$$

(2)

$$N=\frac{1.6\times 10^{-17}}{1.6\times 10^{-19}}=100 \; (\rm possible)$$

(3)

$$N=\frac{1.6\times 10^{-19}}{1.6\times 10^{-19}}=1 \; (\rm possible)$$

(4)

$$N=\frac{3.2\times 10^{-17}}{1.6\times 10^{-19}}=200 \; (\rm possible)$$