BioMedical Admissions Test (BMAT) 2025 – 400 Free Practice Questions to Pass the Exam

The unit of measurement for the power of a lens is dioptres. Lens power, defined as the degree to which a lens converges or diverges light, is mathematically represented as the reciprocal of the focal length measured in meters. Specifically, the formula for power (P) is given by P = 1/f, where f is the focal length in meters.

When the focal length is in meters, the resulting power will be in dioptres, which effectively indicates how strongly the lens is bending light. This unit is crucial in optics, especially in understanding how lenses correct vision; for example, a lens with a power of +2 dioptres can help correct hyperopia (farsightedness) by converging light more effectively.

In contrast, joules represent energy, pascals denote pressure, and meters measure length, none of which are relevant to the characteristic of lens power. Thus, dioptres is the appropriate unit for expressing the power of a lens.