Conical Pendulum & Funnel question from MHT CET 2026 (16 Apr, Shift 1)

Answer: (b)

1. Smooth funnel, semi-vertical angle $\theta$: $N\sin\theta = mg$, $N\cos\theta = \frac{mv^2}{r}$, so $\tan\theta = \frac{gr}{v^2}$.
2. Geometry: $r = h\tan\theta$, which gives $h = \frac{v^2}{g}$.
3. $h = \frac{(0.5)^2}{10} = 0.025$ m
4. So $h = 2.5$ cm, the answer is (b).