Question

what is method of an object of height 7 cm is kept at a distance of 25cm in front of a concave mirror the focal length of the mirror is 15 CM at what distance from the mirror should a screen be kept so as to get a clear image what will be the size and nature of the intage

Answer 1

Reflecting telescopes use mirrors instead of lenses to collect light. Because mirrors have only one reflective surface, they are easier to construct than lenses, which are made from optical glass, and cannot have any occlusions because light must pass completely through them. In addition, mirrors have less spherical aberration, which is a scattering of light that occurs when lenses don't perfectly focus on a single point. Mirrors also reflect all wavelengths of light equally, whereas lenses bend light differently depending on its wavelength.