Q. In a medium sound travels $2\ km$ in $3\ sec$ and in air, it travels $3\ km$ in $10\ sec.$ The ratio of the wavelengths of sound in the two media is
A) $1\ :8$
B) $1\ :18$
C) $8\ :1$
D) $20\ :9$
Explanation
(d) $v \propto \lambda \Rightarrow \frac{\lambda_{1}}{\lambda_{2}} = \frac{v_{1}}{v_{2}} = \frac{2/3}{3/10} = \frac{20}{9}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.