Respuesta :
Answer:
Refraction
Explanation:
When we say that the power of a lens is one dioptre, we are referring to its ability to refract light. Specifically, a lens with a power of one dioptre has a focal length of one meter. This means that parallel rays of light passing through the lens will converge to a point one meter away from the lens. Understanding the meaning of one dioptre requires delving into the principles of optics and how lenses interact with light.
In optics, the term "dioptre" (often spelled "diopter" in American English) is a unit of measurement used to quantify the refractive power of a lens. Refractive power refers to the ability of a lens to bend or refract light as it passes through. It is a crucial concept in optics, particularly in the design of corrective lenses for vision correction and in the study of optical systems.
To understand the meaning of one dioptre, let's first explore the concept of focal length. The focal length of a lens is the distance between the lens and its focal point—the point at which parallel rays of light converge or from which they appear to diverge after passing through the lens. Focal length is a fundamental property of lenses and is directly related to their refractive power.
The formula that relates refractive power (P), focal length (f), and the refractive index of the medium (n) is:
\[ P = \frac{1}{f} \]
Where:
- \( P \) is the refractive power of the lens in dioptres (D),
- \( f \) is the focal length of the lens in meters (m), and
- \( n \) is the refractive index of the medium.
For a lens with a refractive power of one dioptre (\( P = 1 \, D \)), the focal length (\( f \)) is equal to one meter (\( f = 1 \, m \)). This means that parallel rays of light passing through the lens will converge to a point one meter away from the lens. Conversely, if the lens has a negative power of one dioptre (\( P = -1 \, D \)), it has a focal length of negative one meter, indicating that the light rays appear to diverge from a point one meter behind the lens.
The concept of dioptres is central to the design of corrective lenses for vision correction. For example, individuals with myopia (nearsightedness) have difficulty focusing on distant objects because light from distant objects converges in front of the retina instead of on it. To correct myopia, a diverging lens (concave lens) with negative power is used. The power of the corrective lens is measured in negative dioptres to ensure that the focal point of the lens is shifted backward, allowing distant objects to be focused properly on the retina.
Similarly, individuals with hyperopia (farsightedness) have difficulty focusing on nearby objects because light from nearby objects converges behind the retina. To correct hyperopia, a converging lens (convex lens) with positive power is used. The power of the corrective lens is measured in positive dioptres to ensure that the focal point of the lens is shifted forward, allowing nearby objects to be focused properly on the retina.
In addition to corrective lenses, the concept of dioptres is relevant in various optical systems, such as telescopes, microscopes, cameras, and binoculars. Understanding the refractive power of lenses is essential for designing optical systems that produce clear and magnified images.
In summary, when we say that the power of a lens is one dioptre, we are indicating that the lens has a focal length of one meter and can refract light such that parallel rays converge to a point one meter away from the lens. This concept is fundamental in optics, particularly in the design of corrective lenses for vision correction and in the study of optical systems.
