A current of 15.0 A flowing for 30 seconds results in a total charge of 450 C. This translates to approximately 2.81 x 10^21 electrons flowing through the device. The calculation uses the charge of a single electron to find the total number of electrons.
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The provided sentences required comma placements to enhance clarity. Commas serve to indicate pauses and to separate distinct elements within a sentence. Each corrected sentence now follows standard grammatical conventions for comma usage. ;