A-level Physics (Advancing Physics)/Charge/Worked Solutions

1. How much charge do 1234 electrons carry?

1234 x 1.6 x 10^-19 = 1.9744 x 10¹⁶ C = 197.44 aC (attocoulombs)

2. How many electrons does is take to carry 5 C of charge?

5 = 1.6 x 10^-19 x n

$n=\frac{5}{1.6\times 10^{-19}}=31.25\times 10^{18}\text{ C}=31.25\text{ EC (exacoulombs)}$

3. The total charge on 1 mole of electrons (6 x 10²³ particles) is equal to 1 faraday of charge. How many coulombs of charge are equal to 1 faraday?

1 faraday = 6 x 10²³ x 1.6 x 10^-19 coulombs = 96000 coulombs = 96 kC