Question

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

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

Answer 1

The correct option is A

$2\times {10}^{16}$

Let $n$ be the number of electrons hitting the target.

Current given $i$ = $3.2mA$

Charge of electron (e) = $-1.6\times {10}^{-19}$

We know $i=\frac{Q}{t}$

Charge flowing per second $Q$ = $3.2\times {10}^{-}3C$

Number of electrons hitting target per second $n$ = $\frac{3.2\times {10}^{-3}}{1.6\times {10}^{-19}}=2\times {10}^{16}$