Question

The length of a second's pendulum on the surface of the earth is equal to 99.49 cm. True or false.

• A. True
• B. False

Answer 1

The correct option is A True

The time period of seconds pendulum T = 2 seconds, acceleration due to gravity at earth g= 980 $\frac{cm}{s^2}$,It '$l$' is the length of pendulum,

$l=\frac{T^{2}g}{4{\pi }^2}\Rightarrow l=\frac{4\times 980}{4\times {\left(\frac{22}{7}\right)}^2}=\frac{4\times 980\times 49}{4\times 489}=99.49$