2. Questions Bank
  3. JEE Main & Advanced
  4. Mathematics
  5. Conic Sections

JEE Main & Advanced Mathematics Conic Sections Question Bank Ellipse

  • question_answer
    If the distance between a focus and corresponding directrix of an ellipse be 8 and the eccentricity be 1/2, then length of the minor axis is

    A)            3     

    B)            \[4\sqrt{2}\]

    C)            6     

    D)            None of these

    Correct Answer: D

    Solution :

               \[\frac{a}{e}-ae=8\].  Also \[e=\frac{1}{2}\]Þ \[a=\frac{8e}{(1-{{e}^{2}})}=\frac{8.4}{2(3)}=\frac{16}{3}\]                    \[\therefore b=\frac{16}{3}\sqrt{\left( 1-\frac{1}{4} \right)}=\frac{16}{3}\frac{\sqrt{3}}{2}=\frac{8\sqrt{3}}{3}\]                    Hence the length of minor axis is \[\frac{16\sqrt{3}}{3}\].


You need to login to perform this action.
You will be redirected in 3 sec spinner