Question

A current of 1.6 mA flows through a conductor. If charge on an electron is –1.6 × 10^-19 coulomb, find the number of electrons that will pass each second through the cross section of that conductor.

Answer 1

Current, I = 1.6 mA = 1.6 × 10^-3 A

Charge, Q = -1.6 × 10^-19 coulomb

t = 1 sec

Charge flowing through the conductor in one second

I = `"Q"/"t"`

Q = I × t

Substituting the values in the formula above we get,

Q = 1.6 × 10^-3 × 1

= 1.6 × 10^-3

No. of electrons = `(1.6 xx10^-3)/(1.6xx10^-19)`

= `10^16`

Therefore, the number of electrons that will pass each second through the cross section of that conductor = 10¹⁶