Question

If a charge on the body is $-1nC$, then how many electrons are present on the body ?

• A. $1.6\times 10^{19}$
• B. $6.25\times 10^9$
• C. $6.25\times 10^{27}$
• D. $6.25\times 10^{28}$

Answer 1

Answer: (B)

Step 1: Quantization of charge
We know that charge on a body is quantized and can be given as:
$q=Ne$
where, $N$ is number of electrons present on the body, $e$ is the
charge on an electron
Step 2: Substitute the values
From equation (1)
$-1\times 10^{-9}C=-1.6\times 10^{-19}C\times N$ $N=\frac{10^{-9}}{1.6\times 10^{-19}}=6.25\times 10^9\text{ electrons. }$