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← JEE Main 2022 · 26 Jun · Shift 2
MathematicsSingle correct+4 / -1Question 14 of 90

JEE Main 2022 · 26 Jun · Shift 2, Mathematics question 14

If the plane 2x+y−5z=02x+y-5z=0 is rotated about its line of intersection with the plane 3x−y+4z−7=03x-y+4z-7=0 by an angle of π2\dfrac\pi2, then the plane after the rotation passes through the point :

Choose one option
Answer and worked solution

Official answer: C

Rotated plane P1+λP2=0P_1+\lambda P_2=0 perpendicular to P1P_1: 2(2+3λ)+(1−λ)−5(−5+4λ)=30−15λ=02(2+3\lambda)+(1-\lambda)-5(-5+4\lambda)=30-15\lambda=0, so λ=2\lambda=2.

Plane. 8x−y+3z−14=08x-y+3z-14=0.

Check. (1,0,2)(1,0,2): 8+6−14=08+6-14=0 ✓.

(C)