A simple pendulum has a time period 

A simple pendulum has a time period  T₁ when on the earth’s surface and T₂  when taken to a height R above the earth’s surface, where R is the radius of the earth. The value of T₂/T₁ is

(a)  1                                         (b) √2

(c)   4                                         (d)  2

Answer: d