Question

Vectors A^➙ = Pi^˄ – 2Pj^˄ – k^˄ and Vector B^➙ = – 3i^˄ + 2j^˄ – 14k^˄ are perpendicular to each other. Then p = … 

(A) 3 

(B) 4 

(C) 2 

(D) 1

Answer 1

Correct option: (C) 2

Explanation:

A^➙ ⊥ B^➙ 

A^➙ ∙ B^➙ = 0

(Pi˄ – 2Pj˄ – k˄) ∙ (– 3i˄ + 2j˄ – 14k˄) = 0

∴ – 3P – 4P + 14 = 0

∴ P = 2