CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2007

  • question_answer
    The shortest distance from the point\[(1,2,-1)\] to the surface of the sphere\[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}=54\]is

    A)  \[3\sqrt{6}\]                                     

    B)  \[2\sqrt{6}\]

    C)  \[\sqrt{6}\]                       

    D)         \[2\]

    E)  \[4\]

    Correct Answer: B

    Solution :

    The equation of sphere is \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}=54\] The centre and radius of this sphere are (0, 0, 0) and\[\sqrt{54},\]ie,\[3\sqrt{6}\]. Distance between (1, 2, -1) and (0, 0, 0) is\[\sqrt{6}\]. \[\therefore \]Shortest distance between point \[(1,2,-1)\] and surface of the sphere \[=3\sqrt{6}-\sqrt{6}\] \[=2\sqrt{6}\]


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