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If a⃗=2i^+j^\vec{a} = 2\hat{i} + \hat{j} and b⃗=j^−k^\vec{b} = \hat{j} - \hat{k}, then Match List-I with List-II

LIST-ILIST-II
A. Unit vector along a⃗+b⃗\vec{a}+\vec{b}I. 13(−i^+2j^+2k^)\dfrac{1}{3}\left(-\hat{i}+2\hat{j}+2\hat{k}\right)
B. Unit vector perpendicular to both a⃗\vec{a} and b⃗\vec{b}II. 11
C. ∣a⃗+b⃗∣\left\vert \vec{a}+\vec{b} \right\vertIII. 13(2i^+2j^−k^)\dfrac{1}{3}\left(2\hat{i}+2\hat{j}-\hat{k}\right)
D. a⃗⋅b⃗\vec{a}\cdot\vec{b}IV. 33

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 4

a⃗+b⃗=2i^+2j^−k^\vec{a}+\vec{b} = 2\hat{i}+2\hat{j}-\hat{k} has magnitude 33, so its unit vector is 13(2i^+2j^−k^)\frac{1}{3}(2\hat{i}+2\hat{j}-\hat{k}).

Also a⃗×b⃗=−i^+2j^+2k^\vec{a}\times\vec{b} = -\hat{i}+2\hat{j}+2\hat{k} has magnitude 33, giving unit vector 13(−i^+2j^+2k^)\frac{1}{3}(-\hat{i}+2\hat{j}+2\hat{k}), and a⃗⋅b⃗=1\vec{a}\cdot\vec{b} = 1.

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