Answer:
633 nm
Explanation:
E = Energy difference = 1.96 eV
c = Speed of light = 3×10⁸ m/s
h = Planck's constant = 6.626×10⁻³⁴ J/s
Converting eV to J
1 eV = 1.6×10⁻¹⁹ J
1.96 eV = 1.96×1.6×10⁻¹⁹ Joule = 3.136×10⁻¹⁹ Joule
Photon energy equation
[tex]E=\frac{hc}{\lambda}\\\Rightarrow \lambda=\frac{hc}{E}\\\Rightarrow \lambda=\frac{6.626\times 10^{-34}\times 3\times 10^8}{3.136\times 10^{-19}}\\\Rightarrow \lambda=6.33\times 10^{-7}\ m[/tex]
∴ Wavelength of light emitted by this laser is 633 nm
