1. In a certain semiconducting material the charge carriers each have a charge of 1.6 x 10-19 C. How many are entering the semiconductor per second when the current is 2.0 nA?

The number of charges is 1.25 × 10¹⁰

Explanation:

Current is the amount of charge flowing through a conductor per second. The formula for current (I) is given as:

I = Q/t

Where Q is the charge flowing in coulombs and t is the time taken in seconds.

Given that I = 2.0 nA = 2 × 10⁻⁹ A and t = 1 sec

I = Q / t

Q = It =  2 × 10⁻⁹ × 1 =  2 × 10⁻⁹ C

Since each charge = 1.6 x 10⁻¹⁹ C, therefore:

The number of charges = 2 × 10⁻⁹ C / 1.6 x 10⁻¹⁹ C = 1.25 × 10¹⁰