Questions in circle

Select	Question
	Locus of the middle points of the chords of the circle ${{x}^{2}}+{{y}^{2}}={{a}^{2}}$ which are parallel to $y=2x$ will be
	The length of the chord intercepted by the circle ${{x}^{2}}+{{y}^{2}}={{r}^{2}}$ on the line $\frac{x}{a}+\frac{y}{b}=1$ is
	Middle point of the chord of the circle ${{x}^{2}}+{{y}^{2}}=25$ intercepted on the line $x-2y=2$ is
	If the line $x-2y=k$ cuts off a chord of length 2 from the circle ${{x}^{2}}+{{y}^{2}}=3$ , then $k =$
	From the origin chords are drawn to the circle ${{(x-1)}^{2}}+{{y}^{2}}=1$ . The equation of the locus of the middle points of these chords is
	The polars drawn from (–1, 2) to the circles ${{S}_{1}}\equiv {{x}^{2}}+{{y}^{2}}+6y+7=0$ and ${{S}_{2}}\equiv {{x}^{2}}+{{y}^{2}}+6x+1=0$ , are
	The equation of the diameter of the circle ${{x}^{2}}+{{y}^{2}}+2x-4y-11=0$ which bisects the chords intercepted on the line $2x-y+3=0$ is
	If the lengths of the chords intercepted by the circle ${{x}^{2}}+{{y}^{2}}+2gx+2fy=0$ from the co-ordinate axes be 10 and 24 respectively, then the radius of the circle is
	The equation of the common chord of the circles ${{(x-a)}^{2}}+{{(y-b)}^{2}}={{c}^{2}}$ and ${{(x-b)}^{2}}+{{(y-a)}^{2}}={{c}^{2}}$ is
	The length of common chord of the circles ${{(x-a)}^{2}}+{{y}^{2}}={{a}^{2}}$ and ${{x}^{2}}+{{(y-b)}^{2}}={{b}^{2}}$ is