Question

The length of a seconds pendulum at a height h =2 R from earth surface will be :
(Given : R = Radius of earth and acceleration due to gravity at the surface of earth g =π 2 ms −2)

• A. $\frac{2}{9} m$
• B. $\frac{4}{9} m$
• C. $\frac{8}{9} m$
• D. $\frac{1}{9} m$

Answer 1

Answer: (D)

$\frac{1}{9} m$

Answer 2

T=2πgL​​,g′=9R2GM​=9g​=9π2​
2=2ππ2L​×9​
⇒1=πL​×π3​⇒L=91​m