\(\,\,\, \Rightarrow \,\,\,495 = \left( {1 - \frac{1}{{100}}} \right)\,\,50 \times {10^3}(I)\)
\( \Rightarrow \,I = \frac{{495 \times 100}}{{99 \times 50 \times {{10}^3}}} = 10\,\,mA\,\,\,\,\)
\(\therefore\) \(\frac{N}{t} = \frac{I}{e} = \frac{{10 \times {{10}^{ - 3}}}}{{1.6 \times {{10}^{19}}}} = 6.25 \times {10^{16}}\)