Vector Algebra Question - CBSE

Question

If $\vec{a} = 2\hat{i} + \lambda\hat{j} + \hat{k}$ and $\vec{b} = \hat{i} - 2\hat{j} + 3\hat{k}$ are perpendicular to each other, then $\lambda$ is:
(a) $\dfrac{5}{2}$
(b) $-\dfrac{5}{2}$
(c) $5$
(d) $-5$

Accepted Answer

2 - 2\lambda + 3 = 0 \Rightarrow \lambda = 5/2. [1.0 Mark]

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🎯 Official CBSE Marking Scheme:
Evaluating $\lambda = 5/2$: 1.0 Mark

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