The magnification produced by a plane mirror is 1. When an object is placed in front of a plane mirror, the image formed is virtual, upright, and of the same size as the object. The magnification is defined as the ratio of the size of the image to the size of the object.

**Explanation:**

**1. Characteristic Features of a Plane Mirror:**
- A plane mirror is a flat, smooth surface that reflects light specularly, meaning the angle of incidence is equal to the angle of reflection.
- It forms images by the process of reflection.

**2. Formation of Image in a Plane Mirror:**
- When an object is placed in front of a plane mirror, light rays from the object strike the mirror surface and reflect off it.
- The reflected rays then enter our eyes, allowing us to see the image.
- The image formed in a plane mirror is virtual, meaning it cannot be formed on a screen.
- The image is also upright and of the same size as the object.

**3. Magnification in a Plane Mirror:**
- Magnification is a measure of how much larger or smaller an image appears compared to the actual object.
- In the case of a plane mirror, the magnification is always 1.
- This means that the size of the image is the same as the size of the object.
- Mathematically, magnification (m) is given by the formula:
m = height of image (hi) / height of object (ho) = 1

**4. Significance of Magnification 1:**
- A magnification of 1 in a plane mirror implies that the image is neither magnified nor diminished.
- The image appears to be at the same distance behind the mirror as the object is in front of it.
- This is why the image in a plane mirror appears to be the same size as the object.
- The magnification of 1 also indicates that the image is virtual and upright.

**Conclusion:**
In summary, the magnification produced by a plane mirror is always 1. This means that the size of the image formed is the same as the size of the object. The image is virtual, upright, and appears to be located the same distance behind the mirror as the object is in front of it. The magnification of 1 signifies that there is no magnification or reduction in the size of the image.

The magnification produced by a plane mirror is +1 means that the image formed is virtual, erect and of the same size as that of object.