Question

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

• A. $2\times {10}^{16}$
• B. $5\times {10}^6$
• C. $1\times {10}^{17}$
• D. $4\times {10}^{15}$

Answer 1

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

We know that,
$i=\frac{q}{t}=\frac{ne}{t}$

$\Rightarrow n=\frac{it}{e}$

$n=\frac{3.2\times {10}^{-3}\times 1}{1.6\times {10}^{-19}}=2\times {10}^{16}$

Thus the number of electrons striking the target per second is $2\times {10}^{16}$.