The time period of a simple pendulum is given by the formula: \[ T = 2\pi \sqrt{\frac{L}{g}} \] Where \(L\) is the length of the pendulum and \(g\) is the acceleration due to gravity. At height \(R\) above Earth's surface, \(g\) is reduced slightly, but since we're dealing with small changes in height, the time period will remain approximately the same at a height \(2R\). Thus, \(T_1 = T_2\).