Q 11-03-130JEE MainJEE Main 2021 (20 Jul, Shift 1)Easy
If $\vec A$ and $\vec B$ are two vectors satisfying the relation $\vec A\cdot\vec B = |\vec A\times\vec B|$. Then the value of $|\vec A - \vec B|$ will be:
Answer: (D) $\sqrt{A^2 + B^2 - \sqrt2AB}$
$AB\cos\theta = AB\sin\theta \Rightarrow \theta = 45^\circ$.
$$|\vec A - \vec B| = \sqrt{A^2 + B^2 - 2AB\cos45^\circ} = \sqrt{A^2 + B^2 - \sqrt2AB}$$
Solution by Sreeraj P, M.Sc Physics