The focal length of a convex lens is 0.2 meter. Its power will be

The power of a convex lens (D) with a focal length of 0.2 meter will be +5D. Power (in diopters) is calculated as the reciprocal of the focal length in meters. Given the focal length of 0.2 meter, the power of the lens is 1 divided by 0.2, resulting in +5D. This positive diopter value indicates that the lens converges light rays, focusing them at a point 0.2 meter away from the lens. Convex lenses are commonly used in various optical devices, including cameras, eyeglasses for correcting hyperopia (farsightedness), and magnifying glasses. Understanding lens power is crucial in optometry and ophthalmology for prescribing corrective lenses and understanding optical properties related to refraction and light focusing. Negative diopter values would indicate diverging lenses, which spread out light rays and are used for correcting myopia (nearsightedness). Therefore, the power of the convex lens with a focal length of 0.2 meter is +5D, as per the calculation based on its focal length.