How many electrons move past a fixed reference point every tttd = 1.25 psps if the current is iii = 4.8 î¼aî¼a ? the charge on a single electron is about â1.6ã10â19câ1.6ã10â19c .

38 electrons

Explanation:

From Faraday's first law of electrolysis which states that during electrolysis, the mass of a substance deposited at the electrode is proportional to the quantity of electricity passing through it. Mathematically , M ∝ Q

but M = zQ and from electricity, Q =It, hence the equation becomes M = zIt.

where M = Mass of substance deposited in g, and Q =Quantity of electricity in coulombs(C)

I = current in ampere(A)

t = time in seconds

z = Chemical Equivalent in g/C

hence, given t = 1.25 ps and i = 4.8 μA

Using Q = It = 1.25 ps × 4.8 μA , converting the ps (pico secs) to secs and micro ampere to ampere, Q = 1.25 × 10-12s  × 4.8 × 10-6A = 6 × 10-18C

From 1 mole of electron is equal to the quantity of charge which is also equal to 96500C/mol,

Hence, number of moles of electrons =  6 × 10-18C / 96500C/mol

number of moles = 6.218 ×10-5 × 10-18  = 6.218 × 10-23moles

Recalling that, number of moles = number of electrons / Avogadro's constant and Avogardos constant = 6.023 × 10raised to the power of 23/mol

number of electrons = number of moles × 6.023 × 1023/mol

number of electrons = 6.218 × 10-23moles × 6.023 × 1023/mol  = 37.50 which is approximately 38

Hence 38 electrons moved past the fixed reference point.