Question

The charge of an electron is -1.60x10-19 C. A current of 1 A flows in a wire carried by electrons. How many electrons pass through a cross section of the wire each second?

Answer 1

Answer: $6.241\times 10^{18}$ electrons pass through a cross section of the wire each second.

Explanation:

According to mole concept:

1 mole of an atom contains $6.022\times 10^{23}$ number of particles.

Given : Charge on 1 electron = $1.6\times 10^{-19}C$

Charge on 1 mole of electrons = $1.6\times 10^{-19}\times 6.022\times 10^{23}=96500C$

To calculate the charge passed we use the equation:

$I=\frac{q}{t}$

where,

I = current passed = 1 A

q = total charge = ?

t = time required = 1 sec

Putting values in above equation, we get:

$1A=\frac{q}{1s}\\\\q=1A\times 1s=1C$

When 96500C of electricity is passed , the electrons passed = $6.022\times 10^{23}$

1 C of electricity is passed , the electrons passed = $\frac{6.022\times 10^{23}}{96500}\times 1C=6.241\times 10^{18}$

Hence, $6.241\times 10^{18}$ electrons pass through a cross section of the wire each second.