How many number  of electrons  are present  in a particle which  carries a charge  of 

5.5 x 10^-16  C?

Charge carried by one electron $=1.6022\times {10}^{-19}\mathrm{C}$
Electrons present in $5.5\times {10}^{-16}\mathrm{C}$
$=\frac{5.5\times {10}^{-16}}{1.6022\times {10}^{-19}}=3432$