(d) $T = \mu v^{2} = \mu\frac{\omega^{2}}{k^{2}} = 0.04\frac{\left( \frac{2\pi}{0.004} \right)^{2}}{\left( \frac{2\pi}{0.50} \right)^{2}} = 6.25N$
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.