Question

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

• A. $2\times {10}^{16}$
• B. $5\times {10}^{16}$
• C. $1\times {10}^{17}$
• D. $4\times {10}^{15}$

Answer 1

The correct option is A $2\times {10}^{16}$

The current flowing through X-ray tube can be calculated as:
$I=3.2mA=3.2\times {10}^{-3}A$
$=3.2\times {10}^{-3}C/s$
Charge of an electron $=1.6\times {10}^{-19}C$
$\therefore$ Number of electrons striking the target per second $=\frac{3.2\times {10}^3}{1.6\times {10}^{-19}}$
$=2\times {10}^{16}$
Hence, the correct answer is option (a).