Two insulting plates are both uniformly charged in such a way that the potential difference between them is `V_2-V_1=20V`. (i.e., plate 2 is at a higher potential). The plates are separated by `d=0.1m` and can be treated as infinity large. An electron is released from rest on the inner surface of plate 1. What is its speed when it hits plate 2? (`e=1.6xx10^-19C`, `m_e=9.11xx10^-31kg`)

Options

A. `7.02 xx 10^(12)m//s`
B. `1.87 xx10^(6)m//s`
C. `32 xx 10^(-19) m//s`
D. `2.65 xx 10^(6)m//s`

Answer

D

Explanation

`(1)/(2) mv^(2)=q Deltav`
`V^(2) = (2q Delta V)/(m) =(2xx1.6 xx 10^(-19)xx20)/(9.11 xx 10^(-31))`
`V^(2)=7.02 xx 10^(12)`
`V=2.65 xx 10^(6)m//s`