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Vector — JEE physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceJEE physicsVector1 Mark
MCQ
The angle made by the vector $A=\hat{i}+\hat{j}$ with $x$ - axis is
  • A
    $90^{\circ}$
  • ✓
    $45^{\circ}$
  • C
    $22.5^{\circ}$
  • D
    $30^{\circ}$
✓

Answer

Correct option: B.
$45^{\circ}$
(b)$\begin{aligned}& \vec{A}=\hat{i}+\hat{j} \Rightarrow|A|=\sqrt{1^2+1^2}=\sqrt{2} \\& \cos \alpha=\frac{A_x}{|A|}=\frac{1}{\sqrt{2}}=\cos 45^{\circ} \therefore \alpha=45^{\circ}\end{aligned}$

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