The current in a circuit component is 2.00 μA. How many electrons pass through the component each second?

Question 6

The current in a circuit component is 2.00 μA.

How many electrons pass through the component each second?

A 1.25×10¹³                   B 1.25×10¹⁶                   C 1.25×10¹⁹                   D 1.25×10²⁵

Reference: Past Exam Paper – June 2017 Paper 12 Q32

Solution:

Answer: A.

Current I = 2.00 μA

Current I = 2.00 × 10^-6 A

Charge Q = It

Charge Q = 2.00 × 10^-6 × 1

Charge Q = 2.00 × 10^-6 C

This charge is due to electrons. Each electron has a charge of 1.6×10^-19 C.

1.6×10^-19 C - - - > 1 electron

1 C - - - > 1 / 1.6×10^-19  

2.00×10^-6 C - - - > 2.00×10^-6 / 1.6×10^-19 = 1.25×10¹³ electrons