The locus of the point `P(h, k)` for which the line `hx+ky=1` touches the circle `x^(2)+y^(2)=4`, is

The locus of the point (h,k) for which the line hx+ky=1 touches the circle x^2+y^2=4

The locus of th point (l,m). If the line lx+my=1 touches the circle x^(2)+y^(2)=a^(2) is

The locus of th point (l,m). If the line lx+my=1 touches the circle x^(2)+y^(2)=a^(2) is

The locus of the point (l,m) if the line lx+my=1 touches the circles x^(2)+y^(2)=a^(2) is

If the chord of contact of tangents from a point P(h, k) to the circle x^(2)+y^(2)=a^(2) touches the circle x^(2)+(y-a)^(2)=a^(2) , then locus of P is

If the chord of contact of tangents from a point P(h, k) to the circle x^(2)+y^(2)=a^(2) touches the circle x^(2)+(y-a)^(2)=a^(2) , then locus of P is

Let the point at which the circle passing through (0, 0) and (1, 0) touches the circle x^(2)+y^(2)=9 is P(h, k), then |k| is equal to