Aplane dioptric surface separates two homogeneous media of indexes n ans n'. a is the object and a' its image through the dioptic surface. find the relation between ha and ha' under gauss conditions

At 20∘c, the hole in an aluminum ring is 2.800 cm in diameter. you need to slip this ring over a steel shaft that has a room-temperature diameter of 2.804 cm . 1. to what common temperature should the ring and the shaft be heated so that the ring will just fit onto the shaft? coefficients of linear thermal expansion of steel and aluminum are 12×10−6 k−1 and23×10−6 k−1 respectively.