Concept Simulation $26\mathrm{.}1$ illustrates the concepts that are pertinent to this problem. The angle of incidence at a solid$/$liquid boundary is

$79\mathrm{.}7,$ and the index of refraction of the solid is n $=1\mathrm{.}57.($a$)$ What must be the index of refraction of the liquid such that the direction of

the light entering the liquid is not changed? $($b$)$ What is the largest index of refraction that the liquid can have, such that none of the

light is transmitted into the liquid and all of it is reflected back into the solid?