Question

Orange light of wavelength 0.61 µ m in air enters a block of glass with εr = 1.44. What color would it appear to a sensor embedded in the glass? The wavelength ranges of colors are violet (0.39 to 0.45 µ m), blue (0.45 to 0.49 µ m), green (0.49 to 0.58 µ m), yellow (0.58 to 0.60 µ m), orange (0.60 to 0.62 µ m), and red (0.62 to 0.78 µ m)

Answer 1

Answer:

$0.5083\ \mu m$

Explanation:

$\lambda_0$ = Actual wavelength = $0.61\ \mu m$

$\varepsilon_r$ = Relative permittivity = 1.44

The observed wavelength in the glass is given by

$\lambda=\dfrac{\lambda_0}{\sqrt{\varepsilon_r}}\\\Rightarrow \lambda=\dfrac{0.61}{\sqrt{1.44}}\\\Rightarrow \lambda=0.5083\ \mu m$

The wavelength lies in the range of green light.

Hence, the observed color of light is $0.5083\ \mu m$