Answer:
4.28405172412 eV
Explanation:
c = Speed of light = [tex]3\times 10^8\ m/s[/tex]
h = Planck's constant = [tex]6.626\times 10^{-34}\ m^2kg/s[/tex]
[tex]\lambda[/tex] = Wavelength = 290 nm
Energy is given by
[tex]E=h\dfrac{c}{\lambda}\\\Rightarrow E=6.626\times 10^{-34}\times \dfrac{3\times 10^{8}}{290\times 10^{-9}}\\\Rightarrow E=6.8544827586\times 10^{-19}\ J[/tex]
Converting to eV
[tex]\dfrac{6.8544827586\times 10^{-19}}{1.6\times 10^{-19}}=4.28405172412\ eV[/tex]
The threshold energy is 4.28405172412 eV
