JEE Main 2021 (22 Jul, Shift 2) Physics Q21: Three…

Question

Three particles P, Q and R are moving along the vectors

\vec{A} = \hat{i}+\hat{j}

,

\vec{B} = \hat{j}+\hat{k}

and

\vec{C} = -\hat{i}+\hat{j}

respectively. They strike on a point and start to move in different directions. Now particle P is moving normal to the plane which contains vector

\vec{A}

and

\vec{B}

. Similarly particle Q is moving normal to the plane which contains vector

\vec{A}

and

\vec{C}

. The angle between the direction of motion of P and Q is

\cos^{-1}\left(\frac{1}{\sqrt{x}}\right)

. Then the value of

x

is ________.

Official answer

3

NTA final key.

Accepted Answer

3

JEE Main 22 July 2021, Shift 2, Physics Q21