Which of the following do not form diminished virtual image of a real object ?

Options

A. concave mirror
B. convex mirror
C. plane mirror
D. none of these

Answer

To solve the question "Which of the following do not form diminished virtual images of a real object?", we will analyze the three options provided: concave mirror, convex mirror, and plane mirror.

### Step-by-Step Solution:

1. **Understanding Image Formation by Concave Mirror**:
- A concave mirror can produce a virtual image when the object is placed between the mirror's focus (F) and its pole (P).
- The image formed in this case is virtual, erect, and magnified, not diminished.
- Therefore, a concave mirror does not form a diminished virtual image.

2. **Understanding Image Formation by Convex Mirror**:
- A convex mirror always forms a virtual image regardless of the position of the object.
- The image formed by a convex mirror is virtual, erect, and diminished.
- Therefore, a convex mirror does form a diminished virtual image.

3. **Understanding Image Formation by Plane Mirror**:
- A plane mirror produces a virtual image that is of the same size as the object.
- The image is virtual and erect, but it is neither magnified nor diminished.
- Therefore, a plane mirror does not form a diminished virtual image.

4. **Conclusion**:
- Based on the analysis, the options that do not form a diminished virtual image are the concave mirror and the plane mirror.
- Thus, the correct answer is: **Concave Mirror and Plane Mirror**.