Question

How many electrons should be removed from a conductor so that it acquires a positive charge of 3.5nC?

Answer 1

Electrons are present in all elements whether conductors or insulators but in case of conductors there are free electrons which are present in the outermost shell and they can after gaining energy be removed, thus in this way the body acquires charge.

Complete step by step answer:
We are given the value of charge, q= 3.5 nC
Converting this in to coulombs, we get q= $3.5\times {{10}^{-9}}C$
We know the charge on electron is negative, and here it is mentioned that body acquires $3.5\times {{10}^{-9}}C$of positive charge, this implies equal number of negative charges is removed from it,
From quantization of charge, q=ne
Here n is the number of electrons and e is the charge on each electron.
The magnitude of charge on one electron is $1.6\times {{10}^{-19}}$C
Substituting the values,
$q=ne \\\ \implies 3.5\times {{10}^{-9}}=n\times 1.6\times {{10}^{-19}} \\\ \implies n=\dfrac{3.5\times {{10}^{-9}}}{1.6\times {{10}^{-19}}} \\\ \therefore n\simeq 2\times {{10}^{10}} \\\$

Thus, this much number of electrons should be removed from a conductor so that it acquires a positive charge of 3.5nC.

Additional Information:
The charge is always represented in the form of, q = ne. Here n is an integer and this is called quantization of charge. Also, charge has its conservation law which states that it can neither be created nor be destroyed and total charge in an isolated system is always conserved.

Note:
The magnitude of charge on each electron and proton is the same only they differ in polarity.
Proton sits inside the nucleus and it is the electron which is free to move.