(a) To determine the charge in units of Coulomb, you multiply the current with the time since ampere is coulomb/sec.
17 C/s * (1.9 ms * 1s /1000 ms) = 0.0323 C
(b) To determine the number of electrons, we use the Faraday's law (96500 C per mole electron) and the Avogadro's number (1 mole = 6.022 x 10^23 electrons)
17 C/s * (1 s/ 1000 ms) * (1.9 ms) * (1 mol e/96500 C) * (6.022 x 10^23 e / mole e) = 2.016 x 10^17 electrons
