TS EAMCET 5-Aug-2021 Shift 1 Question Paper

Given, wavelength of blue light in vacuum,
λa=450nm=450×10−9m
Refractive index of medium, µm=1.5
Speed of light in air or vacuum, c=3×108m∕s
λm is the wavelength of light in medium.
whereas vm is the speed of light in medium.
As we know that,
Refractive index of medium with respect to air,
µma‌‌=‌

µm

µa

=‌

λa

λm

∴‌‌λm‌‌=‌

λaµa

µm

‌‌=450×10−9×‌

1

1.5

=‌

4500

15

×10−9
‌‌=3×10−7m
‌ Since, ‌‌‌‌

µm

µa

=‌

c

vm

⇒‌‌vm‌‌=c‌

µa

µm

=3×108×‌

1

1.5

=‌‌2×108ms−1
Since, ‌‌fm=‌

vm

λm

where, fm is frequency of light in medium.
∴‌fm‌‌=‌

vm

λm

⇒‌fm‌‌=‌

2×108

3×10−7

=0.66×1015
‌‌=6.67×1014Hz