## A beam of light is shined on a thin (sub-millimeter thick) single crystal wafer of material. The light source is special since it can be tun

Question

A beam of light is shined on a thin (sub-millimeter thick) single crystal wafer of material. The light source is special since it can be tuned to provide any wavelength of visible light on demand. The specimen is illuminated such that the wavelength of light is increased over time while the transmitted intensity of the light is measured. If the sample becomes transparent when the wavelength is greater than 650 nanometers, what is the band gap of the material, in eV

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1 year 2021-07-31T11:28:53+00:00 1 Answers 37 views 0

## Answers ( )

The band gap of the material is 1.9113 eV

Explanation:

Given data:

λ = wavelength = 650 nm = 650×10⁻⁹m

Question: What is the band gap of the material, E = ?

$$E=\frac{hc}{\lambda }$$

Here

h = Planck’s constant = 6.626×10⁻³⁴J s

c = speed of light = 3×10⁸m/s

$$E=\frac{6.626×10^{-34}*3×10^{8} }{650×10^{-9} } =3.058×10^{-19} J=1.9113eV$$