Question

a current of 4 a flows through an auto mobile headlight. how many electrons flow through the headlight in a time of 2 hrs ?​

Answer 1

Answer:

If a current of 4 A flows through an automobile headlight, the number of electrons flowing through the headlight in time 2 hrs is   $1.8\times 10^{23}$

Explanation:

Given,

Current (I) = 4 A

Time (t)     = 2 hrs = 2$\times 60\times 60 = 7200sec$

we know, The current is the flow of charge per unit time.

current ( I) = $\frac{charge (q)}{time (t)}$

q = n $\times$ e

where 'n' is the number of electrons flowing and 'e' is the charge of the electron.

$e=1.6 \times 10^{-19} \mathrm{C}$

Thus   $I=\frac{q}{t}=\frac{n \cdot e}{t}$

The number of electrons (n) flowing  can be calculated by the equation,

$\mathrm{n}=\frac{\mathrm{It}}{\mathrm{e}}=\frac{4 \times 7200}{1.6 \times 10^{-13}}=18 \times 10^{-2}=1.8 \times 10^{23}$  

Number of electrons flowing through the headlight = $1.8\times 10^{23}$