# The period of oscillation of a simple pendulum is $T = 2 \pi \sqrt{ \large\frac{L}{g}}$. Measured value of L is 20.0 cm known to 1 mm accuracy and time for 100 oscillations of the pendulum is found to be 90 s using a wrist watch of 1 s resolution. What is the accuracy in the determination of g?

3%
Hence (A) is the correct answer.