The diagram represents a metal block. Its sides have lengths $a$, $b$ and $c$, as indicated, and the block’s volume is $V$. Every charge carrier carries a charge of $-q$, and the number density of charge carriers in the metal is $n$. On average, each charge carrier needs time $t$ to travel through the block. What expression gives the current $I$?
- A$I = nqabc$
- B$I = \dfrac{nqV}{t}$
- C$I = \dfrac{nqbc}{t}$
- D$I = nqav$