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1800-102-2727A child was eating food, and suddenly he started playing with the spoon. He saw his face from one side of the spoon, it looked very abnormal and smaller in size. Now he turns the spoon and looks at the face again, he finds that his image is larger in size. He gets confused and goes to the plane mirror in the house, and looks at his normal size image. But what is the problem with the spoon? Why is it not showing the normal image? The spoon can be considered a spherical mirror and the spherical mirror has different properties and functions than a plane mirror. Let's understand the spherical mirror in detail !
Table of content
Spherical mirror
Spherical mirrors are the mirrors that are curved in shape and are the part of an imaginary hollow sphere. Spherical mirrors are constructed from the glass. One surface of the spherical part is silvered and the other part is used for reflection. Spherical mirrors can be of different types.
Types of spherical mirror
The spherical mirrors are basically of two types- concave mirror and convex mirror.
Terminology of spherical mirrors
There are following terms needed to know about the spherical mirror-
Rules of image formation through spherical mirrors
The image formed by a spherical mirror can be traced by using following rules -
(a). When it falls on the concave mirror after the reflection it passes through the focus of the concave mirror.
(b). When it falls on the convex mirror after the reflection it appears to pass through the focus of the convex mirror.
(a). A ray incident from the focus of the concave mirror after the reflection becomes parallel to the principal axis of the concave mirror.
(b). A ray directed towards the focus on a convex mirror after the reflection becomes parallel to the principal axis of the convex mirror.
(a).A ray incident from the center of curvature falls on the concave mirror after reflection it reflects back along the same path.
(b).A ray directed towards the center of curvature after reflection from a convex mirror reflects back along the same path.
(a). An incident ray that falls obliquely on the pole of a concave mirror is reflected obliquely the same as a plane mirror.
(b). An incident ray that falls obliquely on the pole of a convex mirror is reflected obliquely the same as a plane mirror.
Uses of spherical mirror
Practice problems
Q. Draw a ray diagram for image formation through a concave mirror if the object is placed between infinity and center of curvature. Discuss the features of the image.
A. Consider the following steps -
Q. Draw a ray diagram for image formation through a concave mirror if the object is placed between the center of curvature and focus of the mirror. Discuss the features of the image.
A. If the object is between the center of curvature and focus then
The image is formed away from the center of curvature. The size of the image is enlarged. The image is real and inverted.
Q. Discuss the ray diagram for image formation through a concave mirror if the object is placed between the focus and pole of the mirror. And what are the features of the image?
A. When the object is between focus and pole, then
The image is formed behind the mirror, the image is virtual, erect and enlarged in size.
Q. Draw a ray diagram for image formation through a convex mirror if the object is placed between infinity and the pole. Discuss the features of the image.
A. For the image the following steps can be taken -
From the ray diagram we can say an image is formed behind the mirror between pole and focus. As the image is behind the mirror so it is virtual. The image is erect and diminished in size.
Q. Which mirror is used in cars?
A. A convex mirror is used so that maximum things can be observed.
Q. Why do dentists use concave mirrors?
A Concave mirror is used because it produces a bigger image of the tooth, so it can be examined properly.
Q. Is the image seen in the mirror real or virtual?
A. The image seen in the mirror is virtual in nature.
Q. Will the image formed by half of a spherical mirror be half or complete?
A. As every small part of the spherical mirror forms a complete image of the object, so the image will be complete.