Commonly Used Terms in Spherical Mirrors

Commonly Used Terms in Spherical Mirrors

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Sign Convention for Spherical Mirrors

The set of guidelines to set signs for image distance, object distance, focal length, etc for mathematical calculation during an image formation is called the Sign Convention. The sign conventions in the case of the spherical mirrors are made in taking into consideration that the objects are always placed on the left side of the mirror, such that the direction of incident light is from left to right....

Important Points to Remember

According to the sign convention, the distances towards the left of the mirror are negative. Since an object is always placed to the left side of a mirror, therefore, the object distance (u) is always negative. The images formed by a concave mirror can be either behind the mirror (virtual) or in front of the mirror (real). So, the image distance (v) for a concave mirror can be either positive or negative depending on the position of the image. If the image is formed behind a concave mirror, the image distance (v) is positive but if the image is formed in front of the mirror, then the image distance will be negative. In a convex mirror, the image is always formed on the right-hand side (behind the mirror), so the image distance (o) for a convex mirror will be always positive. The focus of a concave mirror is in front of the mirror on the left side, so the focal length of a concave mirror will be negative (and written with a minus sign, say, -10 cm). On the other hand, the focus of the convex mirror is behind the mirror on the right side, so the focal length (and written with a plus sign, say +20 cm or just 20 cm), of a convex mirror is positive. The Focal Length and radius of curvature of a concave mirror are taken negatively. The Focal Length and radius of curvature of a convex mirror are taken positively....

Mirror Formula

The distance of the position of an object on the principal axis from the pole of a spherical mirror is known as object distance. It is denoted by u. The distance of the position of the image of an object on the principal axis from the pole of a spherical mirror is known as the image distance. It is denoted by v....

Magnification (or Linear magnification)

Linear Magnification produced by a mirror is defined as the ratio of the size (or height) of the image to the size (or height) of the object. It is denoted by m. If h’ is the size (or height) of the image produced by the mirror and h is the size (or height) of the object....

Solved Examples on Sign Conventions for Spherical Mirrors

Example 1: A concave mirror produces two times magnified real image of an object placed 10 cm in front of it. Find the position of the image....

Sign Conventions for Spherical Mirrors – FAQs

What is the function of a Convex Mirror?...