question_answer

Let\[\overrightarrow{a},\overrightarrow{b}\]\[\overrightarrow{c}\]be three unit vectors such that\[\overrightarrow{a}\times \left( \overrightarrow{b}\times \overrightarrow{c} \right)=\frac{\sqrt{3}}{2}\left( \overrightarrow{b}+\overrightarrow{c} \right).\]If \[\overrightarrow{b}\]is not parallel to \[\overrightarrow{c}\], then the angle between \[\overrightarrow{a}\]and\[\overrightarrow{b}\]is :- [JEE Main Solved Paper-2016 ]

A) \[\frac{5\pi }{6}\]                                            

B) \[\frac{3\pi }{4}\]

C) \[\frac{\pi }{2}\]                                              

D) \[\frac{2\pi }{3}\]