# Apparent and actual radius (Optics)

• Healthycola
In summary, apparent radius refers to the perceived size of an object while actual radius refers to the true size. In optics, the apparent and actual radius can differ due to the bending of light rays. When light passes through a convex lens, the apparent radius of an object will appear larger than its actual radius. However, in certain cases, such as when light passes through a concave lens, the apparent radius can be smaller than the actual radius. The distance between an object and a lens can also affect the apparent radius, with closer objects appearing larger and further objects appearing smaller. Additionally, the apparent radius of an object can change when viewed from different angles due to the refraction of light.
Healthycola
I know the radius of a circle. I'm taking pictures of the circle as I bring it closer to the camera. Obviously the radius is getting larger. I want to know what the relationship is to find this out? I know the distance from the camera that the circle is at all times.

## 1. What is the difference between apparent and actual radius in optics?

Apparent radius refers to the perceived size of an object, while actual radius refers to the true size of the object. In optics, apparent and actual radius can differ due to the bending of light rays as they pass through different mediums.

## 2. How does the apparent radius change when light passes through a convex lens?

When light passes through a convex lens, the apparent radius of an object placed in front of the lens will appear larger than its actual radius. This is due to the convergence of light rays as they pass through the lens.

## 3. Can the apparent radius of an object be smaller than its actual radius in optics?

Yes, in certain cases the apparent radius of an object can be smaller than its actual radius in optics. This can occur when light rays diverge after passing through a concave lens, causing the object to appear smaller than it actually is.

## 4. How does the distance between an object and a lens affect the apparent radius?

The distance between an object and a lens can affect the apparent radius in optics. When the object is closer to the lens, the apparent radius will appear larger, and when the object is further away, the apparent radius will appear smaller.

## 5. Can the apparent radius of an object change when viewed from different angles?

Yes, the apparent radius of an object can change when viewed from different angles in optics. This is due to the refraction of light as it passes through the lens, causing the apparent size of the object to vary depending on the angle at which it is viewed.

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