An object was placed at the centre of curvature of a concave lens. The image formed by the lens would be ______

Options

A. virtual, erect and same size as the object
B. virtual, erect and smaller than the object
C. real, inverted and larger than the object
D. real, inverted and same size as the object

Answer

To solve the question regarding the image formed by a concave lens when an object is placed at the center of curvature, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Lens Type**:
- A concave lens is a diverging lens, meaning it causes parallel rays of light to spread out (diverge) after passing through it.

2. **Position of the Object**:
- The object is placed at the center of curvature of the lens. For a concave lens, the center of curvature is located on the same side as the object.

3. **Ray Diagram**:
- To visualize the image formation, we can draw a ray diagram.
- Draw a concave lens and mark the center of curvature (C) and the focal point (F).
- Draw an object (let’s say an arrow) at the center of curvature.

4. **Drawing Rays**:
- Draw two principal rays from the top of the object:
- **Ray 1**: A ray parallel to the principal axis that diverges after passing through the lens.
- **Ray 2**: A ray passing through the focal point on the same side as the object, which will emerge parallel to the principal axis after refraction.

5. **Finding the Image**:
- Extend the diverging rays backward (in the direction opposite to the actual path of the rays). The point where these extended rays appear to converge is where the image is formed.

6. **Characteristics of the Image**:
- The image formed by a concave lens is always virtual, erect, and diminished (smaller than the object).
- Therefore, the image will not be real or inverted.

7. **Conclusion**:
- Based on the characteristics derived from the ray diagram and the properties of concave lenses, we conclude that the image formed is virtual, erect, and smaller than the object.

### Final Answer:
The image formed by the lens would be **virtual, erect, and smaller than the object**.

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