NCERT Class 12 · Ch 10 Exercise 10.4 · Q11
NCERT Class 12 Maths · Chapter 10 Vector Algebra · Exercise 10.4 Question 11
Given |a|=3 and |b|=√2/3, which listed angle makes a×b a unit vector?
💡 Concept Hints
- Write the vector components and identify the required direction or geometric relation.
- Use the magnitude, dot-product, cross-product or section formula that matches the requested quantity.
✅ Step-by-Step Solution
Final Answer: B: π/4. The other angle 3π/4 also works but is not listed.
- The cross-product magnitude is |a||b|sin θ=√2 sin θ.
- Set it equal to 1: sin θ=1/√2. In [0,π] both θ=π/4 and θ=3π/4 solve it; among the options choose B.
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