(b) $v = \sqrt{\frac{T}{m}} = \sqrt{\frac{T}{\pi r^{2}\rho}}$ $v \propto \frac{\sqrt{T}}{r} \Rightarrow \frac{v_{A}}{v_{B}} = \sqrt{\frac{T_{A}}{T_{B}}}.\frac{r_{B}}{r_{A}} = \sqrt{\frac{1}{2}.}\frac{1}{2} = \frac{1}{2\sqrt{2}}$
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.