question_answer

The radius of the circle in which the sphere \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}+2x-2y-4z-19=0\] is cut by the plane \[x+2y+2z+7=0\], is     AIEEE  Solved  Paper-2003

A)                         1                             

B) 2                             

C) 3                             

D) 4

Correct Answer: C

Solution :

Equation of sphere is                     Centre of the sphere is (-1, 1, 2) and radius                                 Equation of plane is                     Length of the perpendicular from centre O on the plane is                                         In