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प्रश्न
Define (i) principal focus of a concave mirror, and (ii) focal length of a concave mirror.
उत्तर
Definitions-
(i) Principal focus (F) of a concave mirror – Focus of a concave mirror is the point at which the incident rays, parallel to the principal axis, actually meet after reflecting from the concave mirror.
(i) Focal length (f) – Focal length of a concave mirror may be defined as the distance between its focus and pole.
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संबंधित प्रश्न
An object of height 5 cm is placed perpendicular to the principal axis of a concave lens of focal length 10 cm. If the distance of the object from the optical centre of the lens is 20 cm, determine the position, nature and size of the image formed using the lens formula.
The radius of curvature of a spherical mirror is 20 cm. What is its focal length?
The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?
To construct a ray diagram we use two rays which are so chosen that it is easy to know their directions after reflection from the mirror. List two such rays and state the path of these rays after reflection in case of concave mirrors. Use these two rays and draw ray diagram to locate the image of an object placed between pole and focus of a concave mirror.
According to New Cartesian Sign Convention:
(a) focal length of concave mirror is positive and that of convex mirror is negative
(b) focal length of both concave and convex mirrors is positive
(c) focal length of both concave and convex mirrors is negative
(d) focal length of concave mirror is negative and that of convex mirror is positive
Giving reasons, state the 'signs' (positive or negative) which can be given to the following:
(a) object distance (u) for a concave mirror or convex mirror
(b) image distance (v) for a concave mirror
(c) image distance (v) for a convex mirror
An object is placed at a distance of 10 cm from a concave mirror of focal length 20 cm.
Calculate the image distance.
If an object of 10 cm height is placed at a distance of 36 cm from a concave mirror of focal length 12 cm, find the position, nature and height of the image.
Draw a ray diagram to show the formation of image of an object placed between the pole and focus of a concave mirror. State the position, size and nature of the image.
State whether the following statement is True or False
The sides of an object and its image formed by a concave mirror are always interchanged.
