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Which of the following statements are correct?

(A) i^×(j^×k^)=0⃗\hat{i} \times (\hat{j} \times \hat{k}) = \vec{0}.

(B) If ∣a⃗×b⃗∣=2|\vec{a}\times\vec{b}|=2, a⃗.b⃗=4\vec{a}.\vec{b}=4, then ∣a⃗∣2∣b⃗∣2=6|\vec{a}|^2|\vec{b}|^2=6.

(C) The number of vectors of unit length perpendicular to a⃗\vec{a} and b⃗\vec{b} are 2.

(D) If a⃗\vec{a} and b⃗\vec{b} represent the diagonals of the rhombus, then a⃗.b⃗=0\vec{a}.\vec{b}=0

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 3

(A) j^×k^=i^\hat{j}\times\hat{k}=\hat{i} and i^×i^=0⃗\hat{i}\times\hat{i}=\vec{0}: true.

(B) ∣a⃗∣2∣b⃗∣2=∣a⃗×b⃗∣2+(a⃗⋅b⃗)2=4+16=20|\vec{a}|^2|\vec{b}|^2 = |\vec{a}\times\vec{b}|^2+(\vec{a}\cdot\vec{b})^2 = 4+16 = 20, not 6: false.

(C) the two unit vectors ±a⃗×b⃗∣a⃗×b⃗∣\pm\frac{\vec{a}\times\vec{b}}{|\vec{a}\times\vec{b}|}: true.

(D) rhombus diagonals are perpendicular: true.

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