One body has `2.5 xx 10^13` protons. Now if i carries `-2muc` charge then how many electron are there on this body ?

Options

A. (A) `1.25 xx 10^(13)`
B. (B) `2.5 xx 10^(13)`
C. (C) `3.75 xx 10^(13)`
D. (D) none of above.

Answer

C

Explanation

Suppose there are `n_(e)` electrons in a body.
`therefore q = n_(e)e^(-) + n_(p)e^(+)`
`therefore -2 xx 10^(-6) = n_(e)(-1.6 xx 10^(-19)) + 2.5 xx 10^(13) xx 1.6`
`therefore n_(e) = (6 xx 10^(-6))/(1.6 xx 10^(-19)) = 3.75 xx 10^(13)`