A conductor has been given a charge `-3 xx 10^(-7) C` by transferring electron. Mass increase (in kg) of the conductor and the number of electrons added to the conductor are respectively

Options

A. `2 xx 10^(-16)` and `2 xx 10^(31)`
B. `2 xx 10^(-31)` and `2 xx 10^(19)`
C. `2 xx 10^(-19)` and `2 xx 10^(16)`
D. `2 xx 10^(-18)` and `2 xx 10^(12)`

Answer

D

Explanation

Here, `q = - 3 xx 10^(-7)C`
Charge on one electron, `e = -1.6 xx 10^(-19)C`
`:.` Number of electrons transferred to the conductor is
`n = (q)/(e) = (-3 xx 10^(-7)C)/(-1.6 xx 10^(-19)C) ~~ 2 xx 10^(12)`
Mass of one electron, `m_(e) = 9.1 xx 10^(-31)kg`
Mass increase of the conductor `= m_(e) xx n`
`= 9.1 xx 10^(-31) xx 2 xx 10^(12)~~ 2 xx 10^(-18) kg`