Find the current that flows in a silicon bar of 10-μm length having a 5-μm × 4-μm cross-section and having free-electron and hole densities of 104/cm3 and 1016/cm3, respectively, when a 1 v is applied end-to-end. use μn = 1200 cm2/v · s and μp = 500 cm2/v · s.

Explanation :

It is given that,

Length of silicon bar,

Free electron density,

Hole density,

The total current flowing in bar is the sum of drift current due to hole and the electrons.

where, n and p are electron and hole densities.

we know that

So,

or

Current,

A is the area of bar,

So,

Current,

So, the current flowing in silicon bar is .

not too sure thinking it will always be directed towards the centre of the earth. could be wrong not sure

option number c is the right answer.