Question

the number of electrons flow through cross section of a wire in one second if 1 mili ampere of current is flow through it

Answer 1

HEYA THERE,

we  know that ,

I = Q / T

I = ne / T

n = IT/e

where n is no. of electrons

I , current= 10^-3 A

e , charge on an electron = 1.6 x 10 ^ -19 C

Now ,n =10^-3/ 1.6 x 10 ^-19

n = 6.25 x 10^15 ELECTRONS

Answer 2

Answer:

The number of electrons flowing through the cross-section of the wire is 6.25×10¹⁵.

Explanation:

The current is defined as the amount of charge flowing per unit time i.e.

$I=\frac{Q}{t}$       (1)

Where,

I=current

Q=charge flowing through the cross-section of the wire

t=time

The values given in the question are,

I=1mA=1×10⁻³A

t=1 second

By using equation (1);

$1\times 10^-^3=\frac{Q}{1}$

$Q=1\times 10^-^3 C$         (2)

For charge, we know that it is quantized i.e.

$Q=ne$          (3)

Where,

n=number of electron

e=charge on an electron=1.6×10⁻¹⁹C

By putting equation (2) and the value of e in equation (3) we get;

$1\times 10^-^3=n\times 1.6\times 10^-^1^9$

$n=\frac{1\times 10^-^3}{1.6\times 10^-^1^9}=0.625\times 10^1^6=6.25\times 10^1^5$

Hence, the number of electrons flowing through the cross-section of the wire is 6.25×10¹⁵.