Vectors Question 172
Question: If $ |\vec{A}\times \vec{B}|=\sqrt{3}\vec{A}.\vec{B}, $ then the value of $ |\vec{A}+\vec{B}| $ is
[CBSE PMT 2004]
Options:
A) $ \vec{A} $ and $ \vec{B} $ are perpendicular to each other
B) $ \vec{A} $ and $ \vec{B} $ act in the same direction
C) $ \vec{A} $ and $ \vec{B} $ act in the opposite direction
D)                  $ \vec{A} $  and  $ \vec{B} $  can act in any direction
 Correct Answer: C $ \overrightarrow{A}.\overrightarrow{B}=AB\cos \theta  $                                  In the problem  $ \overrightarrow{A}.\overrightarrow{B}=-AB $ i.e.  $ \cos \theta =-1 $ \  $ \theta =180{}^\circ  $                                  i.e.  $ \overrightarrow{A} $  and  $ \overrightarrow{B} $  acts in the opposite direction.Show Answer
  Answer:
Solution:
 BETA
  BETA 
             
             
           
           
           
          