An ellipse has semi-major axes of lengths 2 and semi-minor axis of length 1. It is slipping between the coordinate axes in the first quadrant while maintaining contact with both x-axis and y-axis.
Q. When the ordinate of the centre of ellipse is 1, a light ray passing through origin and centre of ellipse strikes the tangent at the vertex of the parabola y2 + 4x – 10y – 15 = 0. The reflected ray cuts y-axis at the point
  • a)
    (0, 8)
  • b)
    (0, 10)
  • c)
    (0, –8)
  • d)
    (0, 12)
Correct answer is option 'B'. Can you explain this answer?

JEE Question

Karambir Singh
Jul 22, 2020
You may use the fact that the product of perpendicular distances of any tangent on ellipse from its foci is
always equal to square of semi-minor axis.
Since the path of centre is x2 + y2 = 5 when y = 1, x = 2.
The incident ray passes through origin and (2, 1) ⇒ its equation is y = 1/2x
Given parabola is (y – 5)2 = – 4 (x – 10)
whose vertex (10, 5) lies on y = 1/2x.
The tangent at the vertex is the line x = 10.
Figure shows that OP = 2 (OR) = 10
so reflected ray cuts y-axis at (0, 10) 

This discussion on An ellipse has semi-major axes of lengths 2 and semi-minor axis of length 1. It is slipping between the coordinate axes in the first quadrant while maintaining contact with both x-axis and y-axis.Q.When the ordinate of the centre of ellipse is 1, a light ray passing through origin and centre of ellipse strikes the tangent at the vertex of the parabola y2 + 4x – 10y – 15 = 0. The reflected ray cuts y-axis at the pointa)(0, 8)b)(0, 10)c)(0, –8)d)(0, 12)Correct answer is option 'B'. Can you explain this answer? is done on EduRev Study Group by JEE Students. The Questions and Answers of An ellipse has semi-major axes of lengths 2 and semi-minor axis of length 1. It is slipping between the coordinate axes in the first quadrant while maintaining contact with both x-axis and y-axis.Q.When the ordinate of the centre of ellipse is 1, a light ray passing through origin and centre of ellipse strikes the tangent at the vertex of the parabola y2 + 4x – 10y – 15 = 0. The reflected ray cuts y-axis at the pointa)(0, 8)b)(0, 10)c)(0, –8)d)(0, 12)Correct answer is option 'B'. Can you explain this answer? are solved by group of students and teacher of JEE, which is also the largest student community of JEE. If the answer is not available please wait for a while and a community member will probably answer this soon. You can study other questions, MCQs, videos and tests for JEE on EduRev and even discuss your questions like An ellipse has semi-major axes of lengths 2 and semi-minor axis of length 1. It is slipping between the coordinate axes in the first quadrant while maintaining contact with both x-axis and y-axis.Q.When the ordinate of the centre of ellipse is 1, a light ray passing through origin and centre of ellipse strikes the tangent at the vertex of the parabola y2 + 4x – 10y – 15 = 0. The reflected ray cuts y-axis at the pointa)(0, 8)b)(0, 10)c)(0, –8)d)(0, 12)Correct answer is option 'B'. Can you explain this answer? over here on EduRev! Apart from being the largest JEE community, EduRev has the largest solved Question bank for JEE.