JEE Main 2017MathematicsParabolaMediumMCQ

JEE Main 2017 — Parabola Question with Solution

JEE Main 2017 (09 Apr Online)

Question

If y=mx+c is the normal at a point on the parabola y2=8x whose focal distance is 8 units, then c is equal to:

Choose an option

Show full solutionCorrect option: B
Correct answer
B103

Step-by-step explanation

Let the point on the parabola be P( a t 2 , 2at ) where a=2.

Given distance of this point from focus be 8 units

⇒  at2-a2+4a2t2=64

⇒      at2+1=8

⇒     t2+1=4 ⇒ t2=3

⇒    t=  ±3

Since y=mx+c is normal to the parabola

⇒c=2at+a t 3

⇒c=103

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About this question

This is a previous-year question from JEE Main 2017, covering the Parabola chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.