Question

Which of the following is incorrect about Parabola?

(a) Eccentricity is less than 1

(b) Mathematical equation is x^2 = 4ay

(c) Length of latus rectum is 4a

(d) The distance from the focus to a vertex is equal to the perpendicular distance from a vertex to the directrix

The question was posed to me at a job interview.

My doubt stems from Construction of Parabola in chapter Geometrical Construction of Engineering Drawing

Answer 1

Correct choice is (a) Eccentricity is less than 1

Explanation: The eccentricity is equal to one. That is the ratio of a perpendicular distance from point on curve to directrix is equal to distance from point to focus. The eccentricity is less than 1 for an ellipse, greater than one for hyperbola, zero for a circle, one for a parabola.