Q. A beam of monochromatic blue light of wavelength $4200\ \mathring{\mathrm{A}}$ in air travels in water $(\mu = 4/3)$. Its wavelength in water will be
A) 2800 $\mathring{\mathrm{A}}$
B) 5600 $\mathring{\mathrm{A}}$
C) 3150 $\mathring{\mathrm{A}}$
D) 4000 $\mathring{\mathrm{A}}$
Explanation
(c) $\mu \propto \frac{1}{\lambda} \Rightarrow \frac{1}{4/3} = \frac{x}{4200} \Rightarrow x = 3150\mathring{\mathrm{A}}\ $
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.