Question

write two usages of convex and concave lens

Answer 1

Curving inward, concave lenses cause light to spread out, resulting in a smaller image for the viewer. Despite being less useful than convex lenses,concave lenses have several uses, including in eyeglasses and contacts, flashlights, peepholes, binoculars, telescopes, and in photography.

Answer 2

concave lens is used in correcting myopia and it's also used in camera
convex lens is used in preparing Binocular and correct hypermetropia