Two particles are located at equal distance from origin. The position vectors of those are represented by…

Two particles are located at equal distance from origin. The position vectors of those are represented by $\bar{A}=2 \hat{i}+3 n \hat{j}+2 \hat{k}$ and $\bar{B}=2 \hat{i}-2 \hat{j}+4 p \hat{k}$, respectively. If both the vectors are at right angle to each other, the value of $\mathrm{n}^{-1}$ is _____.

Solution

$\begin{aligned} & \overrightarrow{\mathrm{A}} \cdot \overrightarrow{\mathrm{B}}=0 \\ & 4-6 \mathrm{n}+8 \mathrm{p}=0 \\ & |\overrightarrow{\mathrm{~A}}|=|\overrightarrow{\mathrm{B}}| \\ & 4+9 \mathrm{n}^2+4=4+4+16 \mathrm{p}^2 \\ & 9 \mathrm{n}^2=16 \mathrm{p}^2 \\ & \mathrm{P}=+\frac{3}{4} \mathrm{n} \\ & 4-6 \mathrm{n} \pm 6 \mathrm{n}=0 \\ & 12 \mathrm{n}=4 \\ & \mathrm{n}=\frac{1}{3}\end{aligned}$

Asked in: JEE Main 2025 (23 Jan Shift 1)

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