A compensated pendulum shown if Fig. is in the from of an isosceles Delta of base length `l_1=5`cm and coefficent of linar expansion `alpha_1=18xx10^-6` and side length `l_2` and coefficient of linear expansion `alpha_2=12xx10^-6`. find `l_2` so the the distance of centre of mass of the bob from suspension centre O may remain the same at all the temperature.

Explanation

`(l_(1))/(2) sqrt((alpha_(1))/(alpha_(2)))`