Physics - Vectors Question with Solution | TestHub

According to the question: $\begin{array}{rl}|\vec{A}+\vec{B}|& =|\vec{A}-\vec{B}|\\ \Rightarrow |\vec{A}+\vec{B}{|}^2& =|\vec{A}-\vec{B}{|}^2\end{array}$ $\begin{array}{rl}& A^2+B^2+2AB=A^2+B^2-2AB\\ & 4\vec{A}\cdot \vec{B}=0\\ & \vec{A}\cdot \vec{B}=0\\ & \Rightarrow AB\cos \theta =0\\ & \Rightarrow \theta =90^{\circ }\\ & [\text{As }A=B\text{neqeq}0]\end{array}$