An image which can be obtained on a screen is a called a _________. 

real image 

The correct answer is option 3. real image.

A real image is formed when light rays converge at a specific point after passing through an optical system, such as a lens or a concave mirror.

In optical systems like lenses or mirrors, light rays from an object are refracted or reflected in such a way that they converge at a point on the opposite side of the system. This convergence of light rays creates an image of the object.

A real image is formed at a specific location where the converging light rays intersect. This point is where the image appears to be located when projected onto a screen or observed directly.

Real images are typically inverted compared to the object. This means that if the object is oriented upright, the corresponding real image formed by the optical system will be upside-down.

Real images are generally sharp and well-defined, especially when the optical system is properly focused. This sharpness is due to the precise convergence of light rays at a specific point, resulting in a clear image.

Real images can be projected onto a screen or surface, where they can be observed directly. For example, in a camera or projector, a lens forms a real image on the camera sensor or projection screen, allowing the image to be captured or viewed.

Real images are utilized in various optical devices and systems, including cameras, microscopes, telescopes, and projectors. These devices rely on the formation of real images to capture and display visual information accurately.

Overall, a real image is formed by the actual convergence of light rays at a specific point, resulting in a sharp, inverted image that can be projected onto a screen or observed directly. It is a fundamental concept in optics and is essential for understanding how optical systems produce images.