Q. The circle $x^{2} + y^{2} + 2\lambda x = 0,\ \lambda \in R$, touches the parabola $y^{2} = 4x$ externally. Then
A) $\lambda > 0$
B) $\lambda < 0$
C) $\lambda > 1$
D) None of these
Explanation
(a)
Centre of circle must on negative $x$-axis for that $\lambda$ must be positive as centre of circle is $( - \lambda,\ 0)$
[image:11_image50.emf]
$\therefore$ Option (a) is correct
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.