Q. A boat has green light of wavelength $\lambda\ = \ 500\ nm$ on the mast. What wavelength would be measured and what colour would be observed for this light as seen by a diver submerged in water by the side of the boat? Given, $n_{w} = \frac{4}{3}.$
A) Green of wavelength 376 nm
B) Red of wavelength 665 nm
C) Green of wavelength 500 nm
D) Blue of wavelength 376 nm
Explanation
(d) When light travels from rarer to denser medium its wavelength reduces. Wavelength in water
$= \frac{\lambda_{a}}{\mu_{w}}$
$= \frac{500}{(4/3)\ } = 375\ nm = 376\ nm$ (Blue colour)
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.