A real image, equal in size to the object, is obtained when the object is placed at the centre of curvature in front of a

Options

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

Explanation

To solve the question, "A real image, equal in size to the object, is obtained when the object is placed at the center of curvature in front of a...", we will analyze the properties of different types of mirrors and their image formation characteristics.

### Step-by-Step Solution:

1. **Understand the Types of Mirrors**:
- There are three main types of mirrors: concave, convex, and plane mirrors.
- Each type of mirror has unique properties regarding image formation.

2. **Identify the Characteristics of the Image**:
- The question specifies that the image is real and equal in size to the object.
- Real images are formed on the same side as the object and can be projected onto a screen.

3. **Analyze the Concave Mirror**:
- A concave mirror can form real images.
- When the object is placed at the center of curvature (C), the image formed is also at the center of curvature.

4. **Use the Mirror Formula**:
- The mirror formula is given by:
\[ \frac{1}{f} = \frac{1}{v} + \frac{1}{u} \]
where \( f \) is the focal length, \( v \) is the image distance, and \( u \) is the object distance.
- For a concave mirror, the focal length is negative, and the object placed at C means \( u = -R \) (where R is the radius of curvature).

5. **Determine the Image Distance**:
- When the object is at the center of curvature, the image is also formed at the center of curvature.
- Thus, \( v = -R \) (the image distance is also at C).

6. **Calculate Magnification**:
- Magnification (m) is given by:
\[ m = -\frac{v}{u} \]
- Substituting \( v = -R \) and \( u = -R \):
\[ m = -\frac{-R}{-R} = 1 \]
- A magnification of 1 indicates that the image size is equal to the object size.

7. **Conclusion**:
- Since the image is real and equal in size to the object when placed at the center of curvature, the answer is a **concave mirror**.

### Final Answer:
The answer is a **concave mirror**.