Question

If $PSQ$ is the focal chord of the parabola $y^2=8x$ such that $SP=6$ then the lenght of $SQ$ is, where $S$ is the focus of the parabola

• A. $6$
• B. $4$
• C. $3$
• D. $2$

Answer 1

The correct option is C $3$

Parabola is $y^2=8x$
$\Rightarrow a=2$

$SP=6$

By focal chord property

$\frac{1}{SP}+\frac{1}{SQ}=\frac{1}{a}$
$\Rightarrow \frac{1}{6}+\frac{1}{SQ}=\frac{1}{2}$
$\Rightarrow SQ=3$