(b) $H = \frac{u^{2}\sin^{2}\theta}{2g}\ and\ T = \frac{2u\sin\theta}{g}\ \Rightarrow T^{2} = \frac{4\ u^{2}\sin^{2}\theta}{g^{2}}$ $\therefore\frac{T^{2}}{H} = \frac{8}{g} \Rightarrow T = \sqrt{\frac{8H}{g}} = 2\sqrt{\frac{2H}{g}}$
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.