A steel sphere is to be passed through a circular brass ring.  At 20^o C the outer diameter of sphere is 25 cm and the inner diameter of the ring is 24.9 cm if both are heated together, then temperature at which the sphere will just pass through the ring will be :
(Take coefficient of linear expansion of steel= and that of brass = )

A pendulum clock consists of an iron rod connected to a small, heavy bob.  If it is designed to keep correct time at 20^o C, how fast or slow will it go in 24 h at 40^o C.