Question

The frequency of a light ray is $6\times {{10}^{4}}\,\,Hz$ . Its frequency when it propagates in a medium of refractive index $1.5$, will be:

• A. $1.6\times {{10}^{14}}\,\,Hz$
• B. $9.10\times {{10}^{14}}\,\,Hz$
• C. $6\times {{10}^{14}}\,\,Hz$
• D. $4\times {{10}^{14}}\,\,Hz$

Answer 1

Answer: (C)

$6\times {{10}^{14}}\,\,Hz$

Answer 2

When a ray of light passes from one medium to another, then its frequency does not change, but its speed and wavelength change. Hence, its frequency in a medium of refractive index $1.5$ is $6\times {{10}^{14}}Hz$ .
Note: Intensity of light also changes, because a part of it is reflected.