Question

how many electrons pass through a lamp in one minute if the current be 220 ma?

Answer 1

current = I = 220ma = 220×10^-3 A

time = 1 min = 60 s

charge of one electron = e = 1.6×10^-19 coulombs

total charges = q = ?

number of electrons = n = ?
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q = ne
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I = q/t

I = ne/t

It = ne

It/e = n

220×10^-3×60/1.6×10^-19 = n

22×10¹×10^-3×6×10¹/16×10^-20 = n

132×10^1-3+1/16×10^-20 = n

132×10^-1/16×10^-20 = n

132×10^-1-(-20)/16 = n

132×10^-1+20/16 = n

132×10^19/16 = n

8.25×10^19 = n

so 8.25×10^19 electrons pass through a lamp in one minute if the current be 220 ma
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