Answer :
Velocity will be [tex]3.28\times 10^{-11}m/sec[/tex]
Explanation:
We have given glass surface has a diameter of 1.5 mm
And charge q = 1.60 nC
Radius of electrons orbit r = height of electron above surface + radius of sphere = [tex]=1.6+\frac{1.5}{2}=2.35mm = 0.00235m[/tex]
Force on electron is given by [tex]F=\frac{1}{4\pi \epsilon _0}\frac{qe}{r^2}[/tex], here q is charge on sphere and e is charge on electron
[tex]F=\frac{1}{4\pi \epsilon _0}\frac{qe}{r^2}=\frac{kqe}{r^2}=\frac{9\times 10^9\times 1.6\times 10^{-9}\times 1.6\times 10^{-19}}{0.00235^2}=4.172\times 10^{-13}N[/tex]
This force work as centripetal force
So [tex]F=\frac{mv^2}{r}[/tex]
[tex]4.172\times 10^{-13}=\frac{9.11\times 10^{-31}v^2}{0.00235}[/tex]
v = [tex]=0.0328\times 10^{-9}=3.28\times 10^{-11}m/sec[/tex]
