Multiple choice

A conductor has a constant current of 5 A. How many electrons pass through a cross-section of the conductor in 3 minutes?

  1. 9.375 × 1019

  2. 1440 × 10-19 electrons

  3. 5.625 × 1021

  4. 0.106 × 10-19 electrons

  5. 24 × 10-19 electrons
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A single electron charge is q = 1.6 × 10-19C If N electrons pass through the conductor, the total charge transferred: ∆Q = N×q. If the time needed for the charge to pass through is ∆t, then the current is:I =∆Q/∆t = N×q/∆t; From this, the number of electrons: N = I×∆t/q. ∆t = 3 min. = 3×60 s = 180 s. N = 5 A×180s/ 1.6×10-19C = 5.625×1021electrons Answer: N = 5.625×1021electrons

Keep practicing — related questions