Question

A steady current of $5\mu A$ exists in a conductor.The number of electrons crossing a given section of the conductor in $100\mu s$ is:

• A. $3125\times {10}^6$
• B. $312.5\times {10}^5$
• C. $6.25\times {10}^8$
• D. $625\times {10}^{10}$

Answer 1

The correct option is A $3125\times {10}^6$

$q=It=5\times {10}^{-6}\times {10}^{-4}=5\times {10}^{-10}C$
$N=n\times q=625\times {10}^{16}\times 5\times {10}^{-10}=3125\times {10}^6$ electrons.