The potential difference applied to an X-ray tube is 5k V and the current through it is 3.2 mA. Then, the number of electrons striking the target per second is. (a) `2xx10^16` (b) `5xx10^6` (c ) `1xx10^17` (d) `4xx10^15`.
A. `2 xx 10^(16)`
B. `5 xx 10^(16)`
C. `1 xx 10^(17)`
D. `4 xx 10^(15)`