Answer:
1. telescope
2.
[tex]f = \frac{r}{2} [/tex]
[tex]f = \frac{r}{2} [/tex]f- focal length
[tex]f = \frac{r}{2} [/tex]f- focal length r- the radius of curvature of the mirror
[tex] \frac{1}{f} = \frac{1}{p} + \frac{1}{l} [/tex]
p-the distance of the object from the vertex of the mirror
l-the distance of the figure from the vertex of the mirror