Q. The wavelength of red light from He-Ne laser is 633 $nm$ in air but $474\ nm$ in the aqueous humor inside the eye ball. Then the speed of red light through the aqueous humor is
A) $3 \times 10^{8}\ m/s$
B) $1.34 \times 10^{8}\ m/s$
C) $2.25 \times 10^{8}\ m/s$
D) $2.5 \times 10^{8}\ m/s$
Explanation
(c) $\mu \propto \frac{1}{v} \propto \frac{1}{\lambda}$
$\therefore V \propto \lambda$
$\frac{V_{1}}{V_{2}} = \frac{\lambda_{1}}{\lambda_{2}} \Rightarrow \frac{3 \times 10^{8}}{V_{2}} = \frac{633}{474} \Rightarrow V_{2} = 3 \times 10^{8} \times \frac{474}{633}$
$= 2.25 \times 10^{8}m/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.