Vectors a⃗=3î+2ĵ+9k̂ and b⃗=î+pĵ+3k̂ are perpendicular. Find p/(−15).
Physics · Mixed Chapter
JEE Main Practice

Question

Vectors a⃗=3î+2ĵ+9k̂ and b⃗=î+pĵ+3k̂ are perpendicular. Find p/(−15).

G1 Physics · Accepted Answer

Step 1: For perpendicular vectors, a⃗·b⃗=0. Step 2: 3×1 +2p +9×3 =0 ⇒30+2p=0. Step 3: p=−15; hence p/(−15)=1.