Most Important Selected Qs for JEE AdvancedMathematicsEllipse
A ray of light emerging from the point p(0,4) along the tangent of the ellipse x^2 25 + y^2 16 =1 and strike a circle of radius 65 units and reflected from it. The reflected ray entering inside the ellipse through the focus (-3,0) and strike lower surface of ellipse and gets reflected from it. If the reflected ray returns to the point p(0,4) , then ordinate of the centre of circle is _______
Correct answer
5
Step-by-step solution
Using reflection property of ellipse equation of reflected ray S P is 4 x+3 y=12 ......(1) Solving equation (1) with ellipse, we get A ( 75 17 ,- 32 17 ) Equation of reflected ray BS ^ is 16 x+63+48=0 ....(2) Equation of incident ray PB is y=4 ....(3) Equation of bisector of (2) and (3) with negative slope gives normal to circle at 3 which is 4 x+32 y-53=0 Point B is (- 75 4 , 4 ) , using parametric equation of line ordinate of centre is 5