Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
The magnitude of the projection of the vector $2 \hat{i}+3 \hat{j}+\hat{k}$ on the vector perpendicular to the plane containing the vectors $\hat{i}+\hat{j}+\hat{k}$ and $\hat{i}+2 \hat{j}+3 \hat{k}$ is
MathematicsThree Dimensional GeometryMHT CETMHT CET 2022 (06 Aug Shift 2)
Options:
  • A $\sqrt{\frac{3}{2}}$ units
  • B $\frac{\sqrt{3}}{2}$ units
  • C $\frac{3}{\sqrt{2}}$ units
  • D $3 \sqrt{6}$ units
Solution:
1646 Upvotes Verified Answer
The correct answer is: $\sqrt{\frac{3}{2}}$ units
$\begin{aligned} & \frac{|(2 \hat{i}+3 \hat{j}+\hat{k}) \cdot\{(\hat{i}+\hat{j}+\hat{k}) \times(\hat{i}+2 \hat{j}+3 \hat{k})\}|}{|(\hat{i}+\hat{j}+\hat{k}) \times(\hat{i}+2 \hat{j}+3 \hat{k})|} \\ & =\frac{|(2 \hat{i}+3 \hat{j}+\hat{k}) \cdot(\hat{i}-2 \hat{j}+\hat{k})|}{|\hat{i}+\hat{j}+\hat{k}|} \\ & =\frac{|2-6+1|}{\sqrt{1^2+(-2)^2+1^2}}=\frac{3}{\sqrt{6}}=\sqrt{\frac{3}{2}}\end{aligned}$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.