Vector Algebra Question 252

Question: The position vectors of two points P and Q are $ 3\mathbf{i}+\mathbf{j}+2\mathbf{k} $ and $ \mathbf{i}-2\mathbf{j}-4\mathbf{k} $ respectively. The equation of the plane through Q and perpendicular to PQ is

Options:

A) $ \mathbf{r}.(2\mathbf{i}+3\mathbf{j}+6\mathbf{k})=28 $

B) $ \mathbf{r}.(2\mathbf{i}+3\mathbf{j}+6\mathbf{k})=32 $

C) $ \mathbf{r}.(2\mathbf{i}+3\mathbf{j}+6\mathbf{k})+28=0 $

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

  • The required plane is $ {\mathbf{r}-(\mathbf{i}-2\mathbf{j}-4\mathbf{k})}.\overrightarrow{PQ}=0 $ .