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)

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.