Easy MCQ +4 / -1 PYQ · JEE Mains 2023

Let $\vec{a}$ and $\vec{b}$ be two vectors, Let $|\vec{a}|=1,|\vec{b}|=4$ and $\vec{a} \cdot \vec{b}=2$. If $\vec{c}=(2 \vec{a} \times \vec{b})-3 \vec{b}$, then the value of $\vec{b} \cdot \vec{c}$ is :

  1. A $-48$ Correct answer
  2. B $-60$
  3. C $-84$
  4. D $-24$

Solution

<p>$$\overrightarrow b .\overrightarrow c = \overrightarrow b .(2\overline a \times \overrightarrow b ) - 3\overline b .\overrightarrow b $$</p> <p>$= 0 - 3|\overline b {|^2} = - 48$</p>

About this question

Subject: Mathematics · Chapter: Vector Algebra · Topic: Types of Vectors

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