JEE Main & Advanced Sample Paper JEE Main - Mock Test - 43

  • question_answer
    Equation of line in the plane \[P:2x-y+z-4=0\] which is perpendicular to the line \[L:\frac{x-2}{1}=\frac{y-2}{1}=\frac{z-3}{-2}\] and which passes through the point of intersection of L and P is

    A) \[\frac{x-2}{3}=\frac{y-1}{5}=\frac{z-1}{-1}\]               

    B) \[\frac{x-2}{2}=\frac{y-1}{-1}=\frac{z-1}{1}\]

    C) \[\frac{x+2}{2}=\frac{y+1}{-1}=\frac{z+1}{1}\]

    D) \[\frac{x-1}{3}=\frac{y-3}{5}=\frac{z-5}{1}\]

    Correct Answer: D

    Solution :

    [d] Let the direction ratios of the line be (a, b, c). Then \[\therefore \text{ }2a-b+c=0\]and \[a-b-2c=0\] Solving, we get \[\frac{a}{3}=\frac{b}{5}=\frac{c}{-1}\] Thus, the direction ratios of the line are \[(3,5,-1)\]. Any point on the line L is \[(2+\lambda ,2-\lambda ,3-2\lambda )\]. It lies on the plane P if \[2(2+\lambda )-(2-\lambda )+(3-2\lambda )=4\] \[\Rightarrow \,\,\,\,\,\,\,\,\lambda =-1\] So, the point of intersection of the line and the plane is \[(1,3,5)\]. Hence, the equation of the required line is: \[\frac{x-1}{3}=\frac{y-3}{5}=\frac{z-5}{1}\]


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