What happens to the incoming rays that are parallel to the optical axis after passing through a converging lens
The correct answer and explanation is:
When parallel rays of light pass through a converging lens, they are refracted and converge at a specific point called the focal point. This happens because a converging lens, which is typically thicker at the center than at the edges, bends light rays in such a way that they meet at a single point on the other side of the lens.
The optical axis of the lens is an imaginary line that runs through its center and perpendicular to its surface. When parallel rays enter a converging lens, they are refracted toward this axis. The amount of bending depends on the curvature of the lens and the angle at which the rays strike the lens surface.
As the light passes through the lens, the rays are refracted at different angles, with the center of the lens causing the least bending and the edges causing more bending. This refraction causes the parallel rays to converge and meet at a point called the focal point. The distance between the lens and the focal point is called the focal length.
The focal point is located on the side of the lens opposite to the incoming parallel rays. The exact location of the focal point depends on the curvature and material properties of the lens. For thin lenses, the relationship between the focal length (f) and the radius of curvature (R) can be described by the lens maker’s formula, which accounts for the material of the lens and its curvature.
In practical terms, this principle is used in devices like cameras, magnifying glasses, and optical instruments where parallel rays of light (such as those from a distant object) are brought to focus at a point to create a clear image. The ability of a converging lens to focus parallel rays is fundamental to its optical properties.