Let a be a vector which is perpendicular to the vector 3 i+ 1 2 j+2 k. If a× (2 i+ k)=2 i-13 j-4 k, then the projection of the vector a on the vector…
JEE Main 2022 — Mathematics Vectors & 3D Geometry
2022mcqmedium
Let a be a vector which is perpendicular to the vector 3i^+21j^+2k^. If a×(2i^+k^)=2i^−13j^−4k^, then the projection of the vector a on the vector 2i^+2j^+k^ is
Official previous-year question
Held on 28 Jun 2022 · Verified 6 Jul 2026.
Options
A
31
B
1
C
35
D
37
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Solution
Given, a×(2i^+k^)=2i^−13j^−4k^
Now multiplying both side by (3i^+21j^+2k^) we get,