Answer
a) $3.6\times10^{-2}C$
b) $2.3\times10^{17}$
Work Step by Step
a) Current I= $\frac{Charge (q)}{Time (t)}$
This implies: $q= I\times t= 18 A\times2.0 ms$ $=18C/s\times2.0\times10^{-3}s= 3.6\times10^{-2}C$
b) Number of electrons= Total Charge$\div$Charge on one electron $= \frac{3.6\times10^{-2}C}{1.6\times10^{-19}C}\approx2.3\times10^{17} electrons.$
