Vectors Question 219

Question: If three vectors along coordinate axes represent the adjacent sides of a cube of length b, then the unit vector along its diagonal passing through the origin will be

Options:

A) $ \frac{\hat{i},+,\hat{j},+,\hat{k}}{\sqrt{2}} $

B) $ \frac{\hat{i},+,\hat{j},+,\hat{k}}{\sqrt{3b}} $

C) $ \hat{i},+,\hat{j},+,\hat{k} $

D) $ \frac{\hat{i},+,\hat{j},+,\hat{k}}{\sqrt{3}} $

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Answer:

Correct Answer: D

Solution:

[d] Diagonal vector $ \vec{A},=b\hat{i}+b\hat{j}+b\hat{k} $ or $ A=\sqrt{b^{2}+b^{2}+b^{2}},=,\sqrt{3},b $

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Therefore $ $ \hat{A}=\frac{{\vec{A}}}{A}=,\frac{\hat{i}+\hat{j}+,\hat{k}}{\sqrt{3}} $

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Therefore $ $ \hat{A},=\frac{{\vec{A}}}{A}=,\frac{\hat{i}+\hat{j}+\hat{k}}{\sqrt{3}} $