A charged particle of mass `5 xx 10^(-5) kg` is held stationary in space by placing it in an electric field of strength `10^(7) NC^(-1)` directed vertically downwards. The charge on the particle is

Options

A. `-20 xx10^(-5) muC`
B. `-5 xx10^(-5) muC`
C. `5 xx10^(-5) muC`
D. `20 xx10^(-5) muC`

Answer

B

Explanation

`qE=(mg)implies q=(5xx10^(-5)xx10)/(10^7)`
`=5 xx10^(-11)C=5 xx10^(-5) muC`
Since, E is directed downward, hence q is -ve.