The difference in the number of waves when yellow light propagates through air and vacuum columns of the same thickness is one.
Question:
The difference in the number of waves when yellow light propagates through air and vacuum columns of the same thickness is one. The thickness of the air column is ______ mm. [Refractive index of air = 1.0003, wavelength of yellow light in vacuum = 6000 Å]
Solution:
Thickness $\mathrm{t}=\mathrm{n} \lambda$
So, $\mathrm{n} \lambda_{\mathrm{vac}}=(\mathrm{n}+1) \lambda_{\mathrm{air}}$
$\mathrm{n} \lambda=(\mathrm{n}+1) \frac{\lambda}{\mu_{\mathrm{air}}}$
$\mathrm{n}=\frac{1}{\mu_{\mathrm{air}}-1}=\frac{10^{4}}{3}$
$\mathrm{t}=\mathrm{n} \lambda$
$=\frac{10^{4}}{3} \times 6000 A$
$=2 \mathrm{~mm}$
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