Equation of the plane passing through a point with position vector a and normal to the vector n is:

Equation of the plane passing through a point with position vector a and normal to the vector n is:

• A. (r − a) × n = 0
• B. (r − a) · n = 0
• C. r · a = n
• D. r × a = n

Answer: B) (r − a) · n = 0

Explanation: For any point r on the plane, the vector (r − a) lies in the plane, so it is perpendicular to the normal vector n. Thus, their dot product is zero: (r − a) · n = 0.