Circular Motion (Related PYQs) question from NEET 2013

Answer: (c)

1. For the bob: $T\cos\theta = mg$ and $T\sin\theta = \frac{mv^2}{r}$, so $\tan\theta = \frac{v^2}{rg}$.
2. $\tan\theta = \frac{10^2}{10 \times 10} = 1$
3. $\theta = \frac{\pi}{4}$, so the answer is (c).