A wire contains a steady current of 2 A. The number of electrons that pass a cross section in 2 s is:
C) 6.3 × 1018
D) 1.3 × 1019
E) 2.5 × 1019
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Ampere(A) is defined as Coulomb per second(C/s). Its formula is:
where I - current, Q-charge, and t-time.
Substitute I=2 A and t=2 s to determine the charge passing through the wire.
So, the charge is Q=4C.
To determine the number of electrons, take note of the conversion factor:
(1 electron) `1e=-1.6x10^(-19)C`
Using this yields,
`4C * (1e)/(-1.6x10^(-19)C) = -2.5x10^19 e`
Take the positive value of e.
Hence, the number of electrons that pass though the wire's cross section is (E) `2.5x10^19 ` .
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