Question

In the stimulated emission for a certain helium/neon laser, the energy difference is 1.96 eV. What is the wavelength of light emitted by this laser?

Answer 1

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

$E=\frac{hc}{\lambda}\\\Rightarrow \lambda=\frac{hc}{E}\\\Rightarrow \lambda=\frac{6.626\times 10^{-34}\times 3\times 10^8}{3.136\times 10^{-19}}\\\Rightarrow \lambda=6.33\times 10^{-7}\ m$

∴ Wavelength of light emitted by this laser is 633 nm