Which of the following always forms virtual image for real objects ?

Options

A. Concave lens
B. concave mirror
C. Convex mirror
D. convex lens

Explanation

To determine which optical device always forms a virtual image for real objects, we will analyze the options provided: convex lens, concave mirror, concave lens, and convex mirror.

### Step-by-Step Solution:

1. **Understanding the Concept of Virtual Images**:
- A virtual image is formed when light rays appear to diverge from a point, but do not actually converge at that point. This type of image cannot be projected onto a screen and is typically upright.

2. **Analyzing the Convex Lens**:
- A convex lens can form both real and virtual images depending on the position of the object. If the object is placed beyond the focal point, a real image is formed. If the object is placed within the focal length, a virtual image is formed. Therefore, it does not always form a virtual image.

3. **Analyzing the Concave Mirror**:
- A concave mirror can also form both real and virtual images. When the object is beyond the center of curvature, a real image is formed. However, if the object is placed between the focal point and the mirror, a virtual image is produced. Thus, it does not always form a virtual image.

4. **Analyzing the Concave Lens**:
- A concave lens always forms a virtual image for real objects. Regardless of the position of the object, the rays diverge, and when extended backward, they appear to originate from a point behind the lens. The image is always erect and virtual.

5. **Analyzing the Convex Mirror**:
- A convex mirror also always forms a virtual image for real objects. The light rays diverge after reflecting off the mirror, and when extended backward, they appear to originate from a point behind the mirror. The image is always upright and virtual.

### Conclusion:
- The optical devices that always form virtual images for real objects are **concave lens** and **convex mirror**.

### Final Answer:
- **Concave Lens** and **Convex Mirror** are the correct options.