Understanding Image Formation by Different Mirrors 

The question asks to identify the type of mirror that produces an image (reflection) that is smaller than the object (you looking into the mirror). To answer this, we need to understand how different types of mirrors form images.

Types of Spherical Mirrors

Spherical mirrors are curved mirrors that are part of a sphere. They are mainly of two types:

• Concave Mirror: A spherical mirror whose reflecting surface is curved inwards, towards the center of the sphere.
• Convex Mirror: A spherical mirror whose reflecting surface is curved outwards, away from the center of the sphere.

A plane mirror is a flat reflecting surface.

Image Formation by Plane Mirrors

A plane mirror always forms a virtual, erect, and same-size image. The image is located behind the mirror at the same distance as the object is in front of the mirror. Lateral inversion occurs, meaning the image is flipped left to right.

Since the image in a plane mirror is always the same size as the object, it cannot be the mirror that produces a smaller image.

Image Formation by Concave Mirrors

Concave mirrors can form both real and virtual images, depending on the position of the object relative to the mirror's focal point and center of curvature. The characteristics of the image vary:

• Object far beyond the center of curvature: Real, inverted, diminished image.
• Object at the center of curvature: Real, inverted, same-size image.
• Object between the center of curvature and the focal point: Real, inverted, magnified image.
• Object at the focal point: Image formed at infinity (very far away).
• Object between the focal point and the pole: Virtual, erect, magnified image.

While a concave mirror can produce a diminished image (when the object is far away), it doesn't *always* produce a smaller image. It can also produce same-size or magnified images. The question implies finding a mirror that results in a smaller image when a person looks into it, which typically means the person is standing relatively close. In such everyday scenarios (object close to the mirror), a concave mirror would usually produce a magnified virtual image.

Image Formation by Convex Mirrors

A convex mirror always forms a virtual, erect, and diminished image, regardless of the position of the object in front of it. The image is always located behind the mirror, between the pole and the focal point.

The magnification \( m \) for a convex mirror for a real object is always positive (image is erect) and its magnitude \( |m| \) is always less than 1 (\( |m| < 1 \)), indicating a diminished image.

Since a convex mirror consistently produces a smaller image for any real object in front of it, it is the type of mirror described in the question.

Considering the Options

Let's look at the options provided:

• Plano-concave mirror: This is a type of concave mirror. As discussed, concave mirrors can produce various image sizes, including magnified ones, especially when the object is relatively close.
• Concave mirror: Similar to the plano-concave, a concave mirror does not *always* produce a smaller image.
• Plane mirror: Always produces a same-size image.
• Convex mirror: Always produces a smaller (diminished) image.

Based on the image properties, only a convex mirror consistently produces an image smaller than the object for all object positions in front of it.

Therefore, if you look into a mirror and find that your image is smaller than you, the type of mirror is a convex mirror.

Revision Table: Mirror Types and Image Characteristics

Additional Information on Spherical Mirrors

Spherical mirrors are widely used in various applications based on their image formation properties:

• Convex mirrors are often used as rearview mirrors in vehicles and as security mirrors in shops because they provide a wide field of view and always form a small, erect image.
• Concave mirrors are used in headlights (as reflectors), searchlights, shaving mirrors (to get a magnified view), and in telescopes. Their ability to produce a magnified virtual image or focus light is utilized.
• Plane mirrors are used in dressing tables, periscopes, and kaleidoscopes.

Understanding the ray diagrams for each type of mirror helps visualize how images are formed and why they have specific characteristics like size, nature, and orientation.