Question

A electric heater that draws 13.5 a of dc current has been left on for 10 min. how many electrons that have passed through the heater during that time? (e = 1.60 Ã 10-19 c)

Answer 1

By definition, Ampere is a unit of current which is a measure of the amount of charge passing through a point in a circuit per unit  of time, with an equivalent charge of 1.602 x 10^(-19) Coulomb per electron. To determine the number of electrons passing through the heater, we use the definition of the current. We calculate as follows:

13.5 A = 13.5 C per second
Charge = 13.5 C/s (10 min) ( 60 s / 1 min)
Charge = 8100 C 

Number of electrons = 8100 C / 1.602 x 10^(-19) C per electron
Number of electrons = 5.1 x 10^22 electrons

Therefore, there are 5.1 x10^22 electrons that assed through the heater for 10 minutes.