question_answer

Define Brewster angle. Show that the Brewster angle \['{{i}_{B}}'\] for a given pair of transparent media, is related to the critical angle \[{{i}_{e}}\] through the relation, \[{{i}_{c}}={{\sin }^{-1}}\]\[(\cot {{i}_{B}})\].

Answer:

                                        Brewster angle is the angle of incidence at which a beam of unpolarised light falling on a transparent surface is reflected as a beam of completely plane polarised light. According to Brewster law, \[\mu =\tan {{i}_{B}}=\frac{1}{\cot {{i}_{B}}}\] Also,      \[\mu =\frac{1}{\sin {{i}_{C}}}\] On comparing, \[\sin {{i}_{C}}=\cot {{i}_{B}}\] Hence,   \[{{i}_{C}}={{\sin }^{-1}}(\cot {{i}_{B}})\].