Q. If the angle between the vectors A⃗ and B⃗ is θ, the value of the product (B⃗ × A⃗) · A⃗ is equal to :
A) BA² cos² θ
B) BA² sin² θ
C) BA² sin θ cos θ
D) zero
Explanation
[Solution from source] B⃗ × A⃗ is perpendicular to A⃗, so its dot product with A⃗ is zero for any θ. The sin θ and cos θ forms wrongly treat the product as non-zero. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.