3-1.Vectors
hard

यदि $2 \hat{ i }+4 \hat{ j }-2 \hat{ k }$ का प्रक्षेप्य, $\hat{ i }+2 \hat{ j }+\alpha \hat{ k }$ पर शून्य है, तो $\alpha$ का मान होगा $............$।

A

$2$

B

$3$

C

$5$

D

$4$

(JEE MAIN-2022)

Solution

$\overrightarrow{ a } \cdot \overrightarrow{ b }=0$

$\therefore \overrightarrow{ a } \cdot \overrightarrow{ b }=0$

$\therefore 2 \times 1+4 \times 2-2 \times \alpha=0$

$\therefore \alpha=5$

Standard 11
Physics

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