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The vectors  are of the same length. If taken pairwise they form equal angles. If  then what can  be equal to? 

I. î + k̂ 

II. 

Select the correct answer using the code given below. 

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  1. I only
  2. II only
  3. Both I and II
  4. Neither I nor II

Answer (Detailed Solution Below)

Option 3 : Both I and II
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Detailed Solution

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Explanation:

Given:

Also, has same length

⇒  = √2 

Let θ be the angle between the vectors.

⇒ Cosθ = 

(I) Let 

Cosθ = 

All the conditions are satisfied, so it can be vector 

(II) Let 

⇒ 

Cosθ = 

= 

All the conditions are satisfied, so it can be vector 

∴ Option (c) is correct.

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