The angle between the vectors (î + ĵ) and

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The angle between the vectors $(\hat i + \hat j)$ and $(\hat j + \hat k)$ is ....... $^o$

A

$30$

B

$45$

C

$60$

D

$90$

The angle between the vectors $(\hat i + \hat j)$ and $(\hat j + \hat k)$ is ....... $^o$

$(\hat i + \hat j).(\hat j + \hat k) = 0 + 0 + 1 + 0 = 1$

$\cos \theta = \frac{{\vec A.\vec B}}{{|\vec A||\vec B|}} = \frac{1}{{\sqrt 2 \times \sqrt 2 }} = \frac{1}{2}$ 

$\theta = 60^\circ $