question_answer

The critical angle of a prism is \[41.8{}^\circ \]. What should be the refracting angle of a prism, so that a ray after grazing incidence over one lace emerges grazing over the other face?

A)  \[41.8{}^\circ \]         

B)                         \[83.6{}^\circ \]                               

C)  \[60{}^\circ \]                  

D)         \[30{}^\circ \]