JEE Main 2021MathematicsVector AlgebraEasyMCQ

JEE Main 2021 — Vector Algebra Question with Solution

JEE Main 2021 (26 Aug Shift 1)

Question

Let a→=i^+j^+k^ and b→=j^-k^. If c→ is a vector such that a→×c→=b→ and a→·c→=3, then a→·(b→×c→) is equal to:

Choose an option

Show full solutionCorrect option: B
Correct answer
B-2

Step-by-step explanation

We know that, for vectors a→, b→ and c→
a→·(b→×c→)=a→b→c→=c→a→b→

⇒a→·(b→×c→)=(c→×a→)·b→

=-b→·b→

∵a→×c→=b→⇒c→×a→=-b→

=-b→2

=-12+-122

=-2

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About this question

This is a previous-year question from JEE Main 2021, covering the Vector Algebra chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.