A simple pendulum has a time period 5 swhen on the Earth's surface and 10 swhen it is taken to a heighthabove the surface of the Earth. Thenhis equal to

• A)R
  B)R/2
  C)2R/3
  D)3R/2
  
  plzsolve this sir using g'= g ( 1 - 2h/R) and not g' = g R^2/ (R+h)^2
  we should get the same ans but i am not getting the same ans?help
• 
  R2
• 3R2