Q.A current 4A flows through an automobile headlight. How many electrons flow through the headlight in a time 2hrs.

[!TLDR] Q = I*t = 4 A x 7200 s = 28800 C; dividing by the electron charge gives about 1.8x10^23 electrons, matching …

Given $I=4\,\text{A}$, $t=2\,\text{hr}=2\times3600\,\text{s}=7200\,\text{s}$. Using Eq. (11.1), the total charge that flows is $q=It=4\times7200=28800\,\text{C}$. The number of electrons is this total charge divided by the magnitude of a single electron's charge, $N=\dfrac{q}{e}=\dfrac{28 …

Compute total charge from q = I t (Eq. 11.1), then divide by the electron charg …

Forgetting to convert the given time from hours to seconds before multiplying by the current, which would give a char …