When the Object is Placed Beyond C
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The two rays which are considered to obtain the image are:
- a ray passing through the center of curvature
- a ray parallel to the principal axis. The ray passing through the center of curvature retraces its path and the ray which is parallel to the principal axis passes through the focus after reflection. These rays after reflection meet at a point between C and F. The image is inverted, real and diminished
The image is
When the Object is Placed at the Center of Curvature
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Here we consider the two rays, one parallel to the principal axis and the other passing through the focus. The ray of light which is parallel to the principal axis passes through the focus after reflection. The other ray passing through the focus after reflection emerges parallel to the axis. After reflection these rays meet at the center of curvature to form an inverted image, which is real and of the same size as the object.
The image is
When the Object is Between C and F
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Here we consider a ray of light which is parallel to the principal axis and another ray passing through the focus. The ray which is parallel to the principal axis passes through the principal focus and the ray which passes through the focus after reflection emerges parallel to the principal axis. The reflected rays meet at a point beyond C and the image is real, inverted and magnified.
The image is
When the Object is at the Focus
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Here, we consider a ray of light which is parallel to the principal axis and another ray passing through the center of curvature. The ray which is parallel to the principal axis passes through the focus and the ray which passes through the center of curvature retraces its path. The reflected rays are parallel to each other, and would meet only at infinity i.e., the image is formed at infinity and it is a real, inverted, enlarged image of the object.
When the Object is Between the Pole and the Focus
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Here we consider a ray of light which is parallel to the incident ray and another ray which is passing through the center of curvature. The ray which is passing through the center of curvature retraces its path and the other ray which is parallel to the principal axis after reflection passes through the focus. These rays appear to meet behind the mirror when the reflected rays are extended backwards. The image is virtual, erect and magnified.
