If the vector ${\rm{\vec A}} = 2\hat i + 4\hat j\,\,and\,\,{\rm{\vec B}} = 5\hat i + {\rm{p\hat j}}$ are parallel to each other, the magnitude of ${\rm{\vec B}}$ is

NEET UG PHYSICS MCQ: MOTION IN PLANE

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Application +4 | -1

If the vector

\mathrm{\vec A} = 2\hat i + 4\hat j\,\,and\,\,\mathrm{\vec B} = 5\hat i + \mathrm{p\hat j}

are parallel to each other, the magnitude of

\mathrm{\vec B}

View answer and explanation

Correct option: A

5\sqrt 5

Option A (

5\sqrt 5

) is correct because parallel vectors have proportional components, allowing us to determine 'p' and then the magnitude of B.

Practice All Chapter MCQs →

\mathrm{\vec a}\,and\,\mathrm{\vec b}

\mathrm{\vec a}\,and\,\mathrm{\vec b}

\overrightarrow P \,\,.\,\,\overrightarrow Q = 0\,and\,\overrightarrow P \,\, \times \,\,\overrightarrow Q = 0

\overrightarrow Q \,and\,\overrightarrow R

\vec{A}=3 \hat{i}+4 \hat{j}

\vec{B}=6 \hat{i}+8 \hat{j}

A

B

\overrightarrow{\mathrm{A}}

\overrightarrow{\mathrm{B}}

{\cot ^{ - 1}}\left( 2 \right)