Q. The vectors A⃗ and B⃗ are such that |A⃗ + B⃗| = |A⃗ − B⃗|. The angle between the two vectors is :
A) 90°
B) 60°
C) 30°
D) 0°
Explanation
[Solution from source] Squaring both sides, A² + B² + 2A·B = A² + B² − 2A·B, so A·B = 0. The vectors are therefore perpendicular, at 90°. At 0° the sum would be larger than the difference. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.