At the interface of two dielectrics with permittivities 51 and 52, electric field lines are refracted (bent), in other words, the vector D and E change their directions. The following equations hold. Du = DLZ EH1 2 EH2 Here \"i" means the component normal to the interface and "II" means the parallel component. "1" means it is in dielectric 1 and "2" in dielectric 2. As shown in the figure, 61 and 62 are the angles that E makes with the normal direction. Express tan 62 with taanil , 51 and 52