Answer:
Kinetic energy: [tex]6.024*10^{-20}[/tex]
Velocity: [tex]3.64*10^{5}[/tex]
Explanation:
From the equations of the photo-electric effect,
We know:
[tex]hv=hv_0+K.E[/tex]
Where,
1.[tex]h[/tex] is the Planck's constant which is [tex]6.626*10^{-34}[/tex]
2.[tex]v,v_0[/tex] are the frequency of light emitted and threshold frequencies respectively.
3.[tex]K.E[/tex] is the kinetic energy of the electrons emitted.
By fact, we come to know that the threshold frequency of Zn is 300nm
And also [tex]v=\frac{c}{d}[/tex]
Where ,
1. [tex]c[/tex] is the speed of light [tex]=3*10^8[/tex]
2.[tex]d[/tex] is the wavelength.
Thus,
[tex]\frac{hc}{d}=\frac{hc}{d_0}+K.E\\K.E=\frac{hc}{d}-\frac{hc}{d_0}\\K.E=hc*(\frac{1}{d}-\frac{1}{d_0})\\K.E=6.626*10^{-34}*3*10^8*(\frac{1}{275*10^{-9}}-\frac{1}{300*10^{-9}})\\K.E=6.024*10^{-20}kgm^2s^{-2}[/tex]
Now to find velocity:
[tex]K.E=\frac{1}{2}mv^2\\v^2=1.324*10^{11}\\v=3.64*10^5[/tex]
