JEE Main & Advanced Sample Paper JEE Main Sample Paper-42

  • question_answer
    Direction: Assertion- Reaction type. Each of these contains tow statements:  Statement I (Assertion), Statement II (Reason). Each of these questions also has four alternative choices, only one of which is correct. You have to select the correct choices from the codes [a], [b], [c] and [d] given below:
    Statement I: If normal at the ends of double ordinate x = 4 of parabola y2 = 4x meet the curve again at P and P' respectively, then PP' = 12unit.
    Statement II: If normal at \[{{\text{t}}_{\text{1}}}\] of y2 = 4ox meet the parabola again at \[{{\text{t}}_{2}},\] then \[{{\text{t}}_{2}}=-{{t}_{1}}\frac{2}{{{t}_{1}}}.\]

    A)  Statement I is true; Statement II is true; Statement II is not a correct explanation for Statement I

    B)  Statement I is true; Statement II is false.

    C)  Statement I is false; Statement II is true.

    D)  Statement I is true; Statement II is true; Statements is the correct explanation for Statement I.

    Correct Answer: B

    Solution :

    End points of double ordinate x = 4 of parabola y2 = 4 x are \[(4\pm 4).\] \[\Rightarrow \]                        \[{{t}_{1}}=\pm 2\] \[\because \]                 \[{{t}_{2}}=-{{t}_{1}}-\frac{2}{{{t}_{1}}}\]      \[=\pm 3\] \[\Rightarrow \]Points P (9,6) and P' (9,-6). \[\therefore \]\[pp'\sqrt{{{(9-9)}^{2}}+{{(-6-6)}^{2}}}=12\]unit.


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