# Numerical problems on Drift velocity of electrons and electric current-how to solve?

The numerical problems in this post are based on the drift velocity of electrons and electric current. Electric Current is expressed as I = nAve
( see the derivation of electric current and drift velocity equation )

## Numerical problems on Drift velocity of electrons and electric current

1 ] A copper wire has a cross sectional area of 7.85 x 10-7 m2 . The number density of copper is 8.5 x 1028 m-3 . Calculate the mean drift velocity of the electrons through the wire when the current is 1.4 A.

Solution:

The equation to use: I = nAve
=> mean drift velocity = v = I/(nAe)…. ……… (1)

As per the problem statement, A=7.85 x 10-7 m2
n=8.5 x 1028 m-3
and I = 1.4 A
We know, e=1.6 x 10-19

Putting all the values in equation 1, we will get:
v= 1.31 x 10-4 m/s

## Drift velocity worksheet

Now solve the following numerical problems using the same formula.

## Take Away | Suggested reading

Here we have solved numerical problems on drift velocity of electrons and electric current.

You can go through the following related and suggested posts for a better understanding of the topic.