JEE Mains · Maths · STD 12 - 10. vector algebra
Let \(\vec{a}=2 \hat{i}-\hat{j}+5 \hat{k}\) and \(\vec{b}=\alpha \hat{i}+\beta \hat{j}+2 \hat{k}\). If \(((\vec{a} \times \vec{b}) \times \hat{i}) \cdot \hat{k}=\frac{23}{2}\), then \(|\vec{b} \times 2 \hat{j}|\) is equal to.
- A \(4\)
- B \(5\)
- C \(\sqrt{21}\)
- D \(\sqrt{17}\)
Answer & Solution
Correct Answer
(B) \(5\)
Step-by-step Solution
Detailed explanation
\(\vec{a}=2 \hat{i}-\hat{j}+5 \hat{k}, \vec{b}=\alpha \hat{i}+\beta \hat{j}+2 \hat{k}\) \(((\vec{a} \times \vec{b}) \times \hat{i}) \cdot \hat{k}=\frac{23}{2}\), then \(|\vec{b} \times 2 \hat{j}|\) is…
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