Practice question

**Astronomical telescope** in normal adjustment M = -f_o/f_e, f_o objective focal length (m), f_e eyepiece focal length, length L = f_o+f_e, final image at infinity, angular magnification ratio of angles subtended by image and object. For f_o=100 cm, f_e=5 cm, M=-20, inverted, used for celestial observation. The precise curvature of a concave mirror ensures that all parallel rays from a distant object converge accurately to a single focal point. Any deviation in curvature causes spherical aberration, blurring the image and reducing the telescope’s resolving power. Substituting values gives To ensure rays converge to a single point, which matches expected image position and magnification from mirror/lens