JEE Main & Advanced Physics Vectors Question Bank Fundamentals of Vectors

  • question_answer The magnitude of a given vector with end points (4, ? 4, 0) and (? 2, ? 2, 0) must be

    A)             6     

    B)             \[5\sqrt{2}\]

    C)                     4                                         

    D)             \[2\sqrt{10}\]

    Correct Answer: D

    Solution :

                    \[\vec{r}={{\vec{r}}_{2}}-{{\vec{r}}_{1}}=(-2\hat{i}-2\hat{j}+0\hat{k})-(4\hat{i}-4\hat{j}+0\hat{k})\]                    Þ \[\vec{r}=-6\hat{i}+2\hat{j}+0\hat{k}\]             \ \[|\vec{r}|=\sqrt{{{(-6)}^{2}}+{{(2)}^{2}}+{{0}^{2}}}=\sqrt{36+4}=\sqrt{40}=2\sqrt{10}\]

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