Two rods of different metals having the same area of cross section A are placed between the two massive walls as shown is Fig. The first rod has a length `l_1`, coefficient of linear expansion `alpha_1` and Young's modulus `Y_1`. The correcsponding quantities for second rod are `l_2,alpha_2` and `Y_2`. The temperature of both the rods is now raised by `t^@C`.
i. Find the force with which the rods act on each other (at higher temperature) in terms of given quantities.
ii. Also find the length of the rods at higher temperature.