Radiation is incident on a photosensitive surface and the stopping potential is found to be 9 V. What is the maximum velocity of the ejected photo electrons if the specific charge of the electron is `1.8xx10^(11)` C/kg ?

Options

A. `6.6xx10^(5)` m/s
B. `1.8xx10^(6)` m/s
C. `8xx10^(6)` m/s
D. `12xx10^(5)` m/s

Answer

B

Explanation

`1/2mv^(2)=eV " " :.e/m` is the specific charge .
`:.v^(2)=2V(e/m)=2xx9xx1.8xx10^(11)`
`v^(2)=18xx18xx10^(10)`
`v=18xx10^(5)=1.8xx10^(6)m//s`