JEE Main & Advanced
Sample Paper
JEE Main - Mock Test - 34
question_answer
A circle is drawn to pass through the extremeties of the latus ractum of the parabola \[{{y}^{2}}=8x\] and touching the directrix, then radius of this circle is-
A)\[2\sqrt{2}\]
B) 4
C)2
D) 3
Correct Answer:
B
Solution :
[b] Latus rectum is focal chord and every circle on a focal chord as its diameter touches the directrix. Therefore radius \[=\frac{8}{2}=4\]