Q.

The potential difference applied to an X-ray tube is 5 kV and the current through it is 3.2 mA. Then the number of electrons striking the target per second is                  [2002]

1 2×1016  
2 5×106  
3 1×1017  
4 4×1015  

Ans.

(1)

As we know, I=qt=net

∴  No. of electrons striking the target per second

nt=Ie=2×1016