Question

The length of a seconds pendulum is

• A. 99.8 cm
• B. 99 cm
• C. 100 cm
• D. None of these

Answer 1

Answer: (B)

99 cm

Answer 2

$T = 2\pi\sqrt{l/g} \Rightarrow l = \frac{gT^{2}}{4\pi^{2}} = \frac{9.8 \times 4}{4 \times \pi^{2}} = 99\mspace{6mu} cm$